On the server I host I made a sort of "Redstone Workshop" in which, obviously, I create and test Redstone devices. I really like this one device I created and I believe it would be perfect for a Custom Map. This device is a one-use only,possible to reset, of course. I have left the redstone open so if you wish to inspect the machine you may.

Now, on to the device. One Repeater Clock powering 5 Pistons which run at different speeds to create a running effect, the goal is to get from one end to another. I left the bottom open, you may add lava, or a hallway back to the start. It's your choice for your map.