Gunn describes River Rush as "a game where you stand side by side in a river raft, so it's two people playing at once ... to move right, you have to step right; to move left, you have to step left." The game also features a jumping mechanic that, as you might guess, involves players actually leaping into the air. "As you rush down right rapids, you have to jump up and slap floating stars in the air -- the whole raft jumps up every time you do." You'll forgive our reticence, but it only takes one life lesson to learn that jumping into the air blindly near friends and expensive technology almost always results in bad memories. We've asked Microsoft for more information, but the chances of that before the company's E3 press event are about as likely as us going upstream without a paddle.
[Thanks, Jonathan Dixon]