By simply clicking at the following website(s), you're helping out various causes. From hunger, the rainforest, animal rescue, et cetera.

Code:
http://www.thehungersite.com/clickToGive/home.faces?siteId=1

Be sure to click the tabs at the top of the page to visit similar sites.

Also, if you're good at geography, you should check out:
Code:
http://www.freepoverty.com


And, if you're good with words, you should check out:
Code:
http://www.freerice.com

(note, there's no time limit, so you can use a dictionary)

Cheers.

i use freerice all the time

great, now tell these other fools around here to use it as well.