Basically, anything they've played every week for about 6 months - it got to the point where one particular session I could time the pee breaks by which tune was playing - a set would start and I'd know that of these three I knew none and could go for a pee.
There has to be some repetition, but surely not the same set every sodding week!
Same goes for artists - a certain lady piper was first seen in 1984. 2 years later, I saw her again, and she did the identical set, even down to the pause for laughter at the three fingered fiddler joke. It fell flat, because practically everyone else there had heard it too many times as well.... she never did like me for mentioning this to her. Just as well, because I'm not that fond of her either!