Go volunteer. It doesn't matter if you think you're skilled or useful or whatever. It's the responsible thing to do and it's good for you. Here are some non-profits that I have spent time with, and consider either 1) less corrupt than most, 2) so helpful to people that I'm willing to overlook a mild amount of corruption.
(Fort Pierce) Little League
St. Lucie Sheriff's Police Athletic League
Reading Pals of United Way
Habitat For Humanity
Ronald McDonald House
For more info on my volunteer experiences, go here.