A dumb trick that will only work on stupid hot-headed people.
You: I bet I can make you say black.
Idiot: I bet you can't!
You: What are the colors of the American flag?
Idiot: Red, White and, uh, Blue.
You: Told you I could make you say blue
Idiot: Nuh-uh, you said black!
At this point you need to decide whether to bask in your own glory, or point out your victory and risk a serious pounding.