Regarding a female friend with a gorgeous mellow voice who visited recently, in full hearing of that friend:
“Who’s that one that talks not like a lady, like a man?”

F: I need to pee
K: Ok…
F: But it’s darrrrrrrrrk *whine*
K: *sigh* *gets up and goes to bathroom, turns on light*
F: Why did you turn the light on? It’s sometimes exciting in the dark.

Regarding a waiter of Indian appearance:
“What’s that brown man’s name?”

And there was an even more embarrassing one that I’ve (somehow!) forgotten.