I've been called up a few times and have never been selected. At one point in NY, you could donate blood to get out of it.
If it werent for my job getting me out of sitting on panels, I would definitely give up a bag or two.
I took advantage of any quick out they provided. Aside from the motivation of not experiencing a boring real life drama involving some of societies bottom feeders (lawyers), I would have lost a lot of money every day. The pay was around $30 per day, which is great if you're in college, unemployed or a waiter that never gets tipped.