Scratch

I have a new game that I'm currently making called "SP33D T3STS" and I ran out of ideas for minigames. Please help if you have an idea for a minigame that can improve and strengthen a player's "reflexes."

Requirements:
1. It 'can' consist of small white ball, a white border in the background, and arrows.
2. It should 'fit in' on a black background.
3. You can be able to use the arrow keys, spacebar or mouse.

HELP WANTED please!