Community service is a tricky subject when it comes to college admissions. A lot of families are convinced that their student needs to have done it, and if they do, it's going to be a real boost to their student's chances of admission. But neither of those things are necessarily true.
Now, I’m not going to be the guy who says kids shouldn’t do community service (we should all be doing something). But colleges don’t expect that every kid will be out ladling soup at a homeless shelter every weekend. And there is no penalty imposed on a student who chooses to do other things. Colleges just want kids to be productive and to pursue their interests. For some students, that’s doing volunteer work. For others, it’s soccer or jazz band or a part-time job at The Gap.
Whatever the activity, focus more on whether or not you're enjoying it than you do on the total number of hours. If you're going to do community service, do it because you really want to help, not because you're trying to please colleges.
And never, ever ask a college admissions officer how many community service hours are "enough." That's a quick way to make a not-so-good impression.