One from a game where I was a player:
DM: You see a very muscular, barbaric man, wearing no armor and carrying a scythe. (Unfortunately, the DM pronounced it as "sith")
Player 1: A sith?
DM: Yes, a scythe. Why?
Player 2: Why's he carrying a sith?
DM: Why not? That's his weapon.
Me: OMFG! He's wielding Darth Maul!
At this point, the entire table loses it and people are laughing hysterically, even more so because the DM is completely confused about what's going on. I eventually explained the difference in pronunciation between a "scythe" and a "sith" to him, but we never let him live down the time he attacked us with a Sith-wielding barbarian.