I work out, a lot. 6 days a week. Tuesday through Sunday, taking Mondays off only because it is by far the most crowded day. Tuesdays and Wednesdays are crowded too, but not as bad as Monday.
The best days to work out are Saturday and Sunday. On these days the gym is empty. No wait time to use any of the weights.
Only problem with working out, got to go somewhere to do it. If only I had the funds for a home gym.