Jessica Biel. Photo: Jason Kempin/Getty Images
Communities around the world are suffering from water crises -- from not having enough water to not having enough that's drinkable. But with celebrities like Matt Damon, Jessica Biel, Jennifer Connolly, Robin Williams, Rihanna, and others lending their time, talents, and efforts to the cause, there's progress made every day.
1. They climb mountains.
In January 2010, Jessica Biel, Lupe Fiasco, Emile Hirsch, Alexandra Cousteau, and other celebs joined forces for Summit on the Summit, a trek up Mt. Kilimanjaro that raised awareness for the Children's Safe Drinking Water Program.
On their way up the nearly-20,000 foot mountain, they faced altitude sickness, blizzards, and sleep deprivation -- and let their guard down long enough for MTV to capture the whole thing as part of a documentary that caught the attention of a younger generation.
2. They give up gifts.
What do you get for the celebrity that has everything? If you're a fan of Adam Lambert, Jessica Biel, Justin Bieber, Will Smith, or Alyssa Milano, then you make a donation in their honor to Charity: Water, which is focused on bringing clean water to underdeveloped nations.
All of those celebs -- and others -- donated their birthday to the organization, raising $46,000 (Bieber), $92,000 (Milano), and thousands more from their fans.
3. They donate their tap water.Video: YouTube UNICEF added a little A-list panache to its Tap Project -- which asked for donations from restaurant patrons who ordered tap water to help bring clean water to developing countries -- with Celebrity Tap.
The organization enlisted Robin Williams, Adrian Grenier, Taylor Swift, Rihanna, Selena Gomez, and Dwight Howard to bottle water from their own home tap -- and for a donation as small as $5, fans were entered to win a case of the famous aqua.
4. They start their own projects.
When you're a star as well-known and beloved as Matt Damon, you can bring a lot of positive attention to just about any cause you choose.
And one of his biggest impacts has been through the founding of Water.org, created when WaterPartners International and H2O Africa merged in 2009. The group works closely with communities in Haiti, Bangladesh, India, Kenya, and elsewhere, and also started a microfinance organization, Watercredit, to extend its efforts.
5. They show up -- and speak out.Video: YouTube
A famous face never hurts a good cause. The proof: Jennifer Connolly in a PSA for Charity: Water; Matt Damon narrating this PSA for non profit OneXOne; and Kristen Bell voicing a different Charity: Water video.
But not all of them rely on their speaking skills: Pamela Anderson posed for her 14th Playboy cover in January and donated her paycheck to Waves for Water, which provides water filters to countries with undrinkable water.