Put some ramp borders to keep the player from falling out of the arena:

They started being kind of fun to ride on, but they were too quick and jerky.

So I did the obvious thing and remade new ramps twenty times bigger:

I like the way this guy cruises around, but it could be a LOT better. My worry is that I could spend the whole remaining time just messing with the gamefeel, so I have to be careful...