I watched the video with my jaw dropped. Really.
A few current ideas:
Rain: Have a bunch of blue 1x1 rounds that will randomly fall from the ceiling, timed to disappear when they hit the ground. Dance.
Basketball: Have a floating 1x1 in front of a hoop. Have players attempt to shoot the brick in a spot so that it flies forward and gets the brick in the basket. Alternate version is a giant garbage can.
Extreme Catapult: Have one brick catapult another, which lands and catapults another, which lands and catapults another. Continue as long as you can.
Collapsing Bridge: I've wanted to do one of these even before events were out, where a bridge starts falling apart, and then just collapses. The time lengthening thing was the fact that I'd have to calibrate each brick to fall so it would look like it is falling apart, instead of just kinda...breaking. This makes that a really possibility.
Stargate Kawoosh: Wouldn't kill, but who cares, blue bricks everywhere.
Plunko machine: You know you want to.
These are all possible as far as I can tell.