I used to have more than a few drinks on my cheat days in college, which were usually Saturdays. Sundays were my rest day, so it never affected my workouts. I always kept it to Rum and Diet Coke at bars or parties, or mixed vodka with sugar free, low cal cranberry juice if I was at home. I don't really think it was a big deal, but I'm also not into the whole competing thing, and I've never really had to be concerned with building muscle because of my body type (just keeping what I have).