Jumping for Gold??

Watching the Olympics every now and then I find a sport that I had no idea was in the Olympics or why it's there. My sister talked about race walking (most people might think of this as exercise). And then there's now BMX (are the Olympics taking items from the X-games now?). Finally, Olympic trampolining.

Is this sport really for gymnists that couldn't tumble on the ground? How is this an Olympic sport? What's next? Olympic kick-ball? Olympic skipping? When does the maddness stop?