DonorsChoose.org supports school classrooms with a kind of micro-finance. If a teacher needs funding for classroom projects, he or she can post the project on DonorsChoose, and people can fund it with small contributions and get it done. In many cases, a project is like "get enough pens and paper" if the school district is underfunded.
I got two DonorsChoose efforts going, one's my Giving Page, which I should push heavier. So far, it's gotten $52,346 contributed, supporting 5776 students. (I gotta get my act together, to help more.)
More recently, I started a modest effort to support classrooms in schools that primarily serve military families. (You might recall that I'm piggybacking off an effort by Stephen Colbert.) As a team, we've reached 16,153 students, mostly in military families.
Part of the success of this effort is that I'm personally matching funds up to $25,000, and you can still take part in my personal matching funds effort. There are still 29 efforts to be funded, and I'd really appreciate your help, thanks!