I am continuously running into this issue. To work (or apply for jobs for many of you out there), to volunteer, to have fun, to relax... how to keep this all straight and remain sane?!
The point is, as a mid-twenties-er trying to make a name for myself and figure out where I want to go and be, I find keeping up my momentum is the biggest key to success (yes, I just used the phrase "key to success"...enter vomit).
Sure, on a Tuesday night, I am tempted by the cheese-bucket reality TV my roommates are watching on the boob. Sure, at least 30 percent of the time I give into the temptation to slouch on into my new comfy couches and go numb for a while.
My more important point: Don't deny that YOU DO have the time to fit in SOME form of volunteering on, say, a bi-weekly basis (minimum).
Better yet... Your enthusiasm will motivate me and the others around you to do something interesting. And let's face it, we could all use a little more excitement in our (actual) lives.