In this reprise of a now-classic Stanford psychological experiment from the 1960s, kids are put in a room with a marshmallow and told they can either eat it immediately or wait until the researcher gets back, and they'll be given a second marshmallow. Hilarity ensues as the kids suffer marshmallow temptation.
Check more at http://www.eatmedaily.com/2009/09/psychological-experiments-in-self-control-the-marshmallow-test/