I've talked about Kiva before, but I firmly believe that you can't talk about it enough.
In a nutshell, Kiva allows you to lend money to people all over the world who struggle to make a living. I've made nine loans so far, the majority of which have already been paid back in full while one's still running. I got to support a fish selling business in Cambodia, a food market in Uganda, a general store in Iraq, and a pharmacy in Ghana, among others. I won't lie to you: for me, Kiva is as much about the instant gratification of getting my money somewhere it'll actually do some good (something you rarely can be sure of with donations) as it is about the helping people. Helping people to help themselves, that is; it's still a loan, not a donation.
You can lend as little as $25 US, and right now, you don't even have to pay up. Simply click here
for a $25 free trial loan, no strings attached. You get to give away money for free. If that's not reason enough to at least try this out, I don't know what might be. (They do say that supplies of free trials are limited, but seeing how Kiva has grown over the years, I really don't know where they draw the line.)
In the interest of full disclosure: if 20 of you make a loan by August 14th, they might give me a sweater for it, though I'm not sure that's valid outside of the US. Even if it is, I hope you believe me when I say that spreading the word isn't about a stupid sweater.ETA:
Apparently, all the free loans have been claimed already. I still say it's worth checking out the site if you have a little to spare, though.