Skipped most of this thread as I just finished season 2 but I'm just going to throw in that I love this show and I'm going to finish all of the current seasons by the end of the week (and the great thing, is I'm already re-watching season 1 with my brother after convincing him to watch it); I'll probably go back and reread everything after I finish. My favorite episodes so far are Epidemiology, Advanced Dungeons & Dragons, Paradigms of Human Memory (them paying homage to a fanvid [and Harmon spending a bunch of his own money to get the rights to the song] was just something I really loved) & Remedial Chaos Theory (first episode I saw, over a year ago, loved it but never got around to checking it out further).