I've got two, both from my college days. Both with the same DM, both for essentially the same reason.
The first campaign was the first I'd ever played in with this DM. He was enerally pretty good. Towards tehe end of the campaign though, we got involved in a world-shattering adventure, and the DM had us getting help from a bunch of high level NPC's - all higher level than us. The players ran the NPC's but they were 3-4 levels above the regular PC's, so we were totally outshined.
The kicker, though, was after the big confrontation. The dungeon was wiped out in essentially a magical nuclear explosion, but the artifact behind all the evil (a black gemstone) was unharmed. We scried on it, and it was sitting there in the middle of the crater.
We had dealt with this artifact before, and knew how to handle it. However, none of us could teleport, and one of the surviving NPC's could. He was an elven wizard with a 21 INT or something like that. I very carefully explained to him not to touch the evil, bad artifact. And what does he do? He teleports there and trieds to pick up the damned thing. It was like the end of Time Bandits. That was it; we went on another adventure after that, looking for the now-possessed elf, but my PC and another PC started just talking about how we were taking a vacation, and we only hung around bars, and went to the beach, and totally ignored any and all plot hooks. "Someone higher level than us will handle it," we'd say. The game dies out soon after.
The second campaign, the DM (unbeknownst to us) talked one of the players into playing one of the DM's own PC's - a 1st level illusionist. Of course, the PC was also a 21st level Archmage - the DM wanted him to hit mega levels in both classes, this being 1st edition. He wasn't supposed to use any of his mega-wizard powers, but of course, the DM put us in situations where we were outclassed, because he knew we had the extra power to back him up.
Eventually, we made it to Ravenloft. We were 7th level. The DM, in order to make the adventure a challenge for his own PC, boosted Strahd to 16th level wizard (I think the original I-6 he was 9th). We were utterly wiped out. TPK, although we never actually went through the drudgery of playing it out.
The thing is, he wasn't a bad DM, he just had a couple of serious blind spots in his DM'ing makeup.