Over the next four months 10% of sticker sales will go to… Vim!
Unless you're a programmer and/or system administrator this probably doesn't excite you one bit. Vim is a text editor, mostly used for things such as fiddling with configuration files and programming. It's a powerful toy, but not one the average computer user is likely to ever use.
So why Vim? It's partly because it's my editor of choice, and partly because all money donated to Vim goes to ICCF Holland, a charity helping orphans in Kibaale, Uganda. Vim is so-called charity ware; users are encouraged to make a donation, which goes directly to a good cause. It's an interesting concept, and it seems to work for ICCF Holland: a fair amount of the charity's income comes from Vim users.
A good starting point for finding out more about ICCF's work is the video embedded here (if you don't have Flash installed you may want to download the movie). The ICCF website contains lots more information, including interesting reports from its treasurer, Bram Moolenaar - who also happens to be the author of Vim.
If you're interested in Vim the obvious place to start is the Vim website. That said, if you're using Linux or Mac OS X you may want to dive into the terminal and enter
vimtutor for a relatively short (but comprehensive) tutorial.