Rocky Horror Picture Show.
Same as above, but even more pretentious. The plot, such as it is, can be summed up in this phrase: A bunch of perverts dance to rock music while the audience yells back random stuff. The end.
To be fair, the movie itself is only a 'cult classic' BECAUSE at the midnight shows at theatres (and I used to attend them occassionally in the 1980ies when it was something interesting to do); the entire audience effectively participated in an MSTK 3000 style sendup of it as it aired (and new or changed comeback lines that were good stuck and were used in later viewings, etc.) NOBODY should ever be forced to actually watch that film in it's 'original' form.
How are people who have never seen this film (or at least have never been in an audience for it), supposed to learn how to do a proper audience response? Do you just go with friends who'd previously done it, and they teach you?
Do the DVDs, for example, have a 'how-to' audience response track?