2 Hidden Cameras – HVX 200 and Sony Z1U
A bunch of Kids
1 Marshmallow each

Not an original idea, but very fun to make.

worshiphousemedia.com/mini-movies/14675/The-Marshmallow-Test

Used in a series on temptation: watermarkradio.com/index.php?id=153&channel=237&series=150&message=2