Game marathons became something of a fad last year, but the original's still the best. Year two of the Super Mario Marathon, which raised more than $10,000 in 2008, is already past $16,000.
Update/Clarification: My remarks above failed to consider Desert Bus for Hope, which is both a year older than the Mario Marathon, is cited as one of the Mario Marathon's inspirations, and has raised more than $90,000 in its two drives - $70,000 of that coming last year. Desert Bus's organizers will be doing it again this year. Not only is it a great drive for a great cause, its use of Desert Bus is unbeatably novel and hilarious. The marathoners will be enduring a zillion hours of torment again in November.
If you remember last year's charity drive, you know the drill for this year's: Participants Brian Brinegar, John Groth and Chris Deckard are playing all seven Super Mario Bros. games. (2008 Marathoner Dan May is out of the country, but checking in via chat on the team's live stream.) They're taking donations for the Child's Play charity, which is affiliated with more than 40 hospitals worldwide and is dedicated to helping children in their care, with donations of toys and games.