I Heart Kiva
Kiva aggregates small loans--think $25--from (relatively) rich people like you and me, and loans the money to entrepreneurs in the third world to help build their businesses.
So far, they've loaned more than $1M and repayment rates are above 95%.
Kiva is what Web 2.0 should be about--filling a real need, connecting people who can help each other, and making a system more efficient... i.e. not another social bookmarking tool.
I've added a small Kiva ad to the right sidebar. Wish there was some way to get feedback on how it's doing, Kiva folks!
Also, VentureVoice did a podcast with Kiva's Premal Shah. Haven't listened to it yet, but I'm assured it's quite good.
So check out Kiva.org! Their gift certificates make great christmas presents (shh, don't tell, but they certainly will for my family :)