When Captain America walks onto the bridge of the ship, he gives Nick Fury a ten dollar bill. Is this because he is amazed by the ship or is it some reference to the fact that he is from a time when African Americans weren't quite treated as equals yet?
Earlier, when Nick Fury meets Captain America at the gym, they have the following conversation.
NICK FURY: He's called Loki. He's not from around here. There's a lot we'll have to bring you up to speed on if you're in. The world has gotten even stranger than you already know.
STEVE: At this point, I doubt anything would surprise me.
NICK FURY: Ten bucks says you're wrong.
Source: The Avengers transcript on The Internet Movie Script Database
It turns out a camouflaged flying Helicarrier was enough to make Cap pay up.