Guy #1: How much is it?
Me: It's $15 per person for 20 minutes.
Guy #1: For how long?
Me: 20 minutes.
Guy #2: How much is it?
Me: $15 per person for 20 minutes.
Guy #2: Oh yea?  For how long?

I'm still trying to decide if that's worse than the guy who asked, "How long is the hour long ride?"