A drinking game may be out of the question, but that doesnt stop you from making your trip to the cinema that little bit more interesting. It could be something as simple as betting on if an Avenger dies and by whose hand, or you could get far more specific and bet on if Captain America will say "Avengers Assemble" or which AC/DC Tony Stark will make his entrance to. Just keep it harmless and fun, dont bet your life savings.