For me it has to be Data and Joe Piscopo making spastic noises on the holodeck in the name of 'comedy' in "The Outrageous Okuna".
They were doing Jerry Lewis shtick. Apparently they wanted Jerry as The Comic, but there were schedule conflicts so they got Joe instead. So naturally, if you can't get the guy you want, steal his act.
Low points for me were VOY: Fair Haven and VOY: Spirit Folk, for perpetuating Irish stereotypes. I don't know how they ever thought that was a good idea.
They watched Shore Leave.