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.
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.
[Steve gets up, grabs his duffel bag, and another punching bag while Fury is talking.]
FURY: Ten bucks says you’re wrong.
Source: The Avengers screenplay
It turns out a camouflaged flying Helicarrier was enough to make Cap pay up.
FURY (to Steve and Banner): Gentlemen.
[Steve slips Fury the ten dollars he bet earlier, in regards to nothing being able to surprise him. (to Banner) Doctor, thank you for coming.