The first global Twestival was held on February 12, 2009. The idea was simple: Twitter has a bajillion people on it -- so why not get as many people as possible to use Twitter to promote a good cause? Over $250,000 was raised for charity: water, which aided the construction of wells in India, Uganda and Ethiopia.
This year's Twestival is likely to raise even more money, as the social microblogging site expands into the mainstream. Concern Worldwide, a nonprofit organization that seeks to educate the world's poorest people to help end poverty, will be this year's beneficiary. Each city or school has selected a different educational area to support within Concern Worldwide.
So, now you know what Twestival is. How do you get involved?
•Mashable has a comprehensive list of ways to make your impact during Twestival. The most important actions to take are to donate or attend a Twestival event (they're in hundreds of cities around the world).
You can learn about the different programs supported by Concern Worldwide and select a focus for your donation. Any money raised through the sale of Twestival products will also go to Concern Worldwide.
•Twestival's iPhone application has detailed schedules of Twestival events in various cities, plus keeps track of funds raised through ticket sales and donations.
•Download "I Put a Spell on You," a cover of the Screamin' Jay Hawkins classic, by Shane MacGowan, Nick Cave, Johnny Depp and others. Money from sales of the song go to Concern Worldwide's efforts in Haiti.
•Take part in Auction140, which runs through March 26. Prominent figures from the world of music, television, movies and literature are putting personal items up for auction, with raised funds going to Concern. Some of the included items: a piano lesson with Eric Lewis, a phone call from Justin Bieber, a signed poem poster from Margaret Atwood, and a Paris Hilton "bag of goodies."
•Volunteer at a Twestival event. Some of the most prominent events are detailed below:
Los Angeles: HuffPost blogger Shira Lazard is co-hosting L.A. Twestival at the Roxy Theater on the Sunset Strip. There will be DJs, dancing, and a surprise musical performance from a "top alternative band." Tickets are still available.
New York: Good Units by Hudson is the venue for New York Twestival. The highlight of the evening is a raffle, whose prizes included tickets to Late Night with Jimmy Fallon, a Madison Square Garden gift pack. and a Shinoba Ninja prize pack (we guess you have to win it to see what it is).
Toronto: Follow @TwestivalTO on Twitter, and join prominent Toronto DJ Skratch Bastid at the Tryst Nightclub. They've got prizes as well, including a Free BlackBerry Bold 9700, a Toronto Raptors jersey autographed by Chris Bosh, and a swanky "girls night out."
Other cities holding a Twestival: Buffalo, Charleston, Boston, Houston, Sao Paolo, Tokyo, Mumbai, Cairo, London (and about 20 more in Great Britain and Ireland), Copenhagen, Ljubljana, Milan, Paris, and many more.
If you can't make it to any of these, follow along on one of several live streams (which will be posted below once the embed codes are made available) and see what people are tweeting on our Twestival 2010 Live Updates page. And don't forget to tag your tweets with #twestival!