If I had a class or students right now, I would be using this idea, but since I'm not, I'll put it out there. One of my friends tutors a young lady with down's syndrome. Together, they came up with a couple service learning ideas, and decided on reading for Heifer International. The young lady is planning to read 145 books and has asked people for pledges (her note was funny- it said "You can pay me to read" which sounds like some sort of deal my brother tim would have tried on my mom- very enterprising). Anyway, her goal is to buy a water buffalo for a family in India through pledges (anywhere from 10 cents on up per book she reads).
As part of the program at Marian, we had to involve our students in service learning and I only wish I could have done that this spring. I plan on trying something like that with my eventual class.