I understand where you are coming from, we had a 40 hour requirement at my high school.
But I can't help but feel you aren't being creative enough or looking hard enough. I mean I'm sure homeless shelter's need volunteers, as do toy donations for under privileged children, political campaigns need volunteers (see Louie Mantia's contribution to the Obama campaign here: http://louiemantia.com/blog/?p=31), and so do Boys & Girls clubs.
Not to mention taking 1-2 weeks off and helping people in other countries.