Katy Perry might not be able to dance with Elmo on TV, but plenty of charities have benefited from the the buxom rocker showing off her wares on stage. This winter, the Hot ‘N Cold bride of comic Russell Brand was featured on CBS adoption special The 12th Annual A Home for the Holidays. She also took time out of her busy schedule to perform for the troops at VH1 Divas Salute The Troops, a concert for the USO.

Oprah Winfrey’s made a huge impact in the charity spectrum, as the talk show maven not only spends TV airtime informing her audience about the causes she supports, she also reaches into her deep pockets as well. On one instance, the generous Chicago-based media icon gave each member of her studio audience $100 a piece to put toward the charity of their choosing. Her Oprah’s Angel Network “works around the globe to give people the chance to live their best lives.” Said Marc Pollick, president of The Giving Back Fund, a national charity: “There are many generous celebrities, but when you can top a list of celebrity philanthropists three out of four years, as Oprah has, that is saying something.”

It’s anything but ironic that 90s rocker Alanis Morissette has spent years donating her time, name and services to causes such as human rights, women’s rights and abused children, among others. The Canadian singer’s been involved with organizations such as Equality Now, Make Trade Fair, Oxfam and United Cerebral Palsy.

Grammy-award winner Wyclef Jean is recognized as much for his philanthropy as he is for his music these days, as his organization Yéle Haiti was a major hub in recovery efforts after the January earthquake in Haiti, his home country, left more than 1.5 million Haitians homeless. Jean was also partnered up with George Clooney on the TV special Hope For Haiti.

With the Elton John AIDS Foundation, the Crocodile rocker has put his name, time and energy toward those infected or affected by HIV/AIDS to help with their physical, emotional and financial hardship, “enabling them to improve their quality of life, live with dignity and exercise self-determination.” John told the Independent in December 2010: I’ve just got enough time in my life to do some good things for people. I pick and choose. I probably do about 30 charity things a year, but then are 365 days in a year so 30 doesn’t seem that much. And a lot are for my charity.”

Prince Charles stays active in a variety of causes with The Prince’s Charities, a group of 20 non-profit groups, 18 which he’s founded personally. His charities have a vast reach, lending support in spectrums such as business, education and the environment. According to his website, “the charities reflect The Prince of Wales’s long-term and innovative perspective, and seek to address areas of previously unmet need.”

While former President Bill Clinton’s legacy will most likely centered around his political achievements, the Arkansas native’s done plenty to help others, as his charitable reach has extended to causes such as affordable care for those with HIV/AIDS, improving global public health, eliminating poverty and energy conservation, among others.

Bono has complemented his status as a rock icon with that of a well-rounded philanthropist, as the U2 frontman’s been putting his best foot forward toward a smorgasbord of worthy causes for the past 25 years. The Irish rocker said he was inspired to get involved after seeing 1979′s The Secret Policeman’s Ball. Since then, he’s been active to step up for causes including disadvantaged kids, disaster relief, homelessness, hunger, human rights, the mentally disabled, and eliminating racism, among others. For his considerable efforts, he’s been nominated for the Nobel Peace Prize three times.

One of the true good guys in Hollywood, George Clooney’s biggest charitable achievement in 2010 was organizing the gala TV benefit Hope For Haiti during the country’s restoration efforts following the massive earthquake in January. Of course, Clooney’s charitable achievements hardly stop there, as he’s championed every cause from stopping the human rights atrocities in the Darfur region to the homeless to continuing the dream set forth by Dr. Martin Luther King, Jr.

Regardless of what kind of husband he might have been, Tiger Woods has always been straight up when it comes to charitable causes. His Tiger Woods Foundation is aimed towards helping children to “inspire new perspectives and limitless possibilities,” as well as providing “opportunities to be someone.” He donated $3 million to Wyclef Jean’s Yele Haiti charity in the wake of the January earthquake.

Oscar-winner Sean Penn delivered more than 100,000 medical supplies to Haiti after the country’s calamitous January 12 earthquake. According to the Independent, the Milk star “dug trenches, hauled sacks of food, and delivered medicine.” Penn told The Early Show of his considerable efforts: “There’s something that takes over and it’s really an obligation because you see the strength of the people who have never experienced comfort, and the gifts that can give to people like myself and to our country and culture. You see the enormous gaps.”

When he’s not playing pranks, and she’s not Tweeting, Demi Moore and Ashton Kutcher are among Hollywood’s most philanthropic celebs, as their Demi and Ashton Foundation is “working with numerous high-profile celebrities to create awareness about the existence of child sex slavery in the United States and to change cultural attitudes about the issue.”

Funnyman Robin Williams has spread his wealth and celebrity toward a variety of causes, including the American Foundation for AIDS Research, Christopher Reeve Foundation, Lance Armstrong Foundation, Love Our Children USA, Luke Neuhedel Foundation, Muhammad Ali Parkinson Center, St. Jude Children’s Research Hospital and Comic Relief, among others. “No matter what people tell you, words and ideas can change the world,” Williams said.

Ben Stiller is not only one of Hollywood’s most talented actors, he’s also one of the most giving. The Zoolander star has put his time toward causes including abused children, rape victims and pediatric AIDS patients. Stiller collaborated with Save The Children for his own organization STILLERSTRONG, to provide education programs for Haitian children.

John Travolta has been among the A-list’s most giving, as the Pulp Fiction star and wife Kelly Preston established the Jett Travolta Foundation in memory of their son, who tragically passed away at the family’s Bahamas vacation home in 2009. The foundation, according to its’ website, looks “to assist and provide relief to children with vision, hearing, mobility, communication, behavior learning impairments or other special medical, environmental, health or educational needs.”

Among his many, many contributions, the rocker founded the Jon Bon Jovi Soul Foundation to help families in economic despair. With financing, programs and partnerships, the foundation aims to break the cycle of poverty and homelessness. Said the Living On A Prayer singer: “I think volunteerism should be fashionable, that’s my goal.”

Eurythmics singer Annie Lennox has a long history of giving toward causes ranging from AIDS awareness and prevention to African women to Amnesty International. The Here Comes The Rain Again singer told the UK Times that losing her son Daniel in 1988 “had an immense impact on me. It made me realize that the human condition is immensely fragile and strong. At the same time as I lost my son, thousands of people died in a village in Turkey after an earthquake. Curiously enough, I identified with those people. It made me realize that life truly is temporary, and when I hear about people’s tragedies, I … empathize with them.”

Grammy Award-winning soul singer John Legend had lived up to his name as a world-class philanthropist devoted towards causes near and far. Among the organizations he’s put his time and name toward include The Gentlemen’s Fund, a men’s charity; Tide Loads of Hope, which helped Hurricane Katrina victims; and (RED), which assists helps women and children affected by HIV/AIDS in Africa.

Both stars are noted philanthropists, cemented by Jolie’s status as a Goodwill Ambassador for United Nations. In 2010, the red carpet mainstays donated $1 million following the devastating earthquake that destroyed large portions of Haiti. Jolie said, “It is incredibly horrible to see a catastrophe of this size,” while Pitt said, “We understand the first response is critical to serve the immediate needs of countless people who are now displaced from their homes, are suffering trauma, and most require urgent care.”

Justin Bieber’s one of the most successful entertainers in the world these days, so it’s nice to see the teen idol channel his off-the-charts popularity into positive outlets. The Baby singer in late December held an event called Stuff Bieber’s Bus, encouraging concertgoers to donate toys (which were subsequently forwarded to Children’s Healthcare of Atlanta). “It was just something I thought would be really cool,” Bieber said. “I think that it doesn’t really matter what you do. As long as you’re helping other people, why not do it?”

Madonna’s been a standout in terms of giving over the years, as she’s funneled huge sums of time, money and effort towards causes such as eliminating poverty and HIV-AIDS education/prevention, among others. The Material Girl recently sent gift boxes crammed with toys, candy and other goodies to children in orphanages throughout Malawi (the African republic where she adopted daughter Mercy James and son David Banda) along with a note that read, “To my Malawi children on Christmas and Boxing Day. I wish I was with you. See you soon, M.”