MDDN 343: Game Idea.

I have decided to go with my multiplayer 'rob the nest' (crossed with rugby?) style game idea. I think it would be the most fun.

Basics of the gameplay:
-Multiplayer split screen (2 players)
-Players start on opposite sides of the map, and must get to the ball in the middle.
-After they have acquired the ball, they must get it to the other side of the map (the side they didn't start on).
-First player to a certain amount of points (5?) wins.
-First or third person view. Not sure which yet.
-Players are able to tackle/trip each other. This causes the player holding the ball to drop it, allowing the other player to pick it up.
-Player holding the ball moves slower.
-Players trip/stumble if the come into contact with obstacles around the map. 

I still need to work out some sort of context for my game. Why are the players trying to score goals? Are the players human? Animals? When will it be set? Will the map be futuristic? Medieval?

I don't knoooooowwww.