There's another one based on Asterisk called Lenny - it's an old man who plays the whole "can't hear you" card and it works so well. There's a whole channel of Lenny recordings: https://www.youtube.com/watch?v=rcinQuDXYn8
There's a couple of comedians who have specialized in baiting telemarketers[1][2]. It's a whole art form, trying to keep the telemarketer engaged while spinning the most ridiculous yarns. The horny priest, the bill collector, the retarded guy, the deaf guy, the guy who couldn't stop burping.
1. https://www.youtube.com/results?search_query=jim+florentine+...
2. https://www.youtube.com/results?search_query=tom+mabe+telema...