This is fun app from a couple of Youtube stars (Dan and Phil) who initially made the 7 second challenge popular in one of their videos.
Here's a few challenges:
Pretend your Mario and you just saw Luigi get killed by Bowser
What's 4 times 4 divided by 4 plus 4 minus 4 o
Lick both of your elbows
7 seconds...go!
Boom video