So I thought it would be cool to make a map for practicing different flinging techniques and just generally screwing around. I think of it like a skate park: a big open area with lots of interesting terrain rather than obstacles. The way I imagine it, it would have lots of ramps and platforms, and a few buttons which would move or tilt panels different ways. These would serve as player-adopted mini-goals, since the level imposes no goals of its own.
So you'd load it up and like, try to get a handle on what happens if you're doing a fling and turn 180 degrees right before you go into the floor portal for the second time, and try to figure out if that opens up any new maneuvers. With this practice goal in mind, you could hop around and kind of set up a good area to do the test you want, maybe hit a switch to turn a panel from vertical to 45 degrees, and then you try it out.
Is this making sense?
Kind of along the same lines I was also thinking of making a combat practice room with user-activated panels that would open to reveal as few or as many turrets as they wanted to fight at once. Kind of like the X-Men's Danger Room.
What do you guys think?

FLING |[CONNECTOR] \ 

