EvilEngineer is a fully-functioning OSX Test Pattern Generator(Color Bars, Grey Steps, Gradient, Grids) for testing video signals, with a couple of fun features built in "under-the-hood" to provide some backstage shenanigans for your production downtime.
Using the Keyboard Arrow Keys, you can control the size and shape of the Test Patterns by shrinking and squeezing the image, forcing them to realign their projectors or adjust their source configurations.

Instructions:

1.  Connect to Projector(Or switcher input) and fire up EvilEngineer.

2.  Have the Projectionist align the projectors with the EvilEngineer Test Patterns

3.  When they aren't looking, use the Arrow Keys adjust the size and shape of the test pattern.

4.  Show the Projectionist the misalignment, Repeat from step 2.

Easter Egg:
Press 'f' for a surprise.

Disclaimer:
Use at your own risk.  As with any prank, realize there may be consequences, so don't be a jerk.

Currently awaiting Apple Store Approval....

If you'd like early access, head over to Fiverr, and I'll send you a copy, straight-away!