We have this great audio tape floating around our original gaming group. One of the guys who was kind of clueless was running the rest of us through a homebrewed dungeon-crypt. We had suspicions who the boss at the end would be. Sure enough, it was this DM's favorite personal creation, a lich named 'Varnay Carnae'. (Yes, you know you want liches with rhyming names in your campaign, don't you?)
So, our characters, in true munchkin style, began wailing on this lich, using every magic item in the book to deal out mega damage, while trying to avoid his deadly spells. The rounds went on, and damage was dealt, but still Varnay Carnae remained standing. Hell, he didn't even look like he was that damaged.
One of the players started getting hot. He and the DM really didn't get along too well. So you can hear it on the audio tape.
Player: "...double damage for the 20, I do him 36 points of damage."
DM: "OK, he takes it, and launches another fireball."
Player: "Danny, I've kept track. We've done over 300 points to this guy, and he's still standing. That's BS."
DM: "Yes. He doesn't look like he's that hurt."
Player: " You sunuva..."
The rest of us: "Oh crap..."
You can hear things falling and shifting around as our friend launched himself at the GM. It was sad and oh-so-funny. And Varnay Carnae still got away...
