You’re probably familiar with the work of cartoonist Ted Rall, whose work appears on Salon and in many other places. He is raising money for a trip to Afghanistan to report, in his way, on the situation there, and through a website, you can support the trip with small donations.
I really like the micro-granting site Kickstarter, and I’ve supported several projects with ten or twenty dollars here and there. One of the cool things about it is that if a project fails to reach its fund-raising goal, no one’s donation goes through, so projects require a sort of consensus of support.