I fall asleep in anything from a pair of boxers (usually on my bathroom floor while I wait for my shower to warm up...and subsequently let it run cold) to a full outfit (seriously, sometimes even shoes.) This is due largely in part to the fact that I'm a bit of an insomniac, so I tend to do this absolutely adorable thing where I more or less pass out from exhaustion rather than fall asleep. Thus, I sometimes end up falling asleep midday in the clothes I wear to class (and usually end up sleeping through class). When I do fall asleep at a normal hour, shorts and a t shirt. Socks are a no because it's awful for your feet. They need to breathe, man. Seriously, I usually get more upset about falling asleep with socks on than I do about sleeping in class on the occasions when I fall asleep midday.