The Office - Opening scenes from this season's "Costume Contest" Episode (entire video embedded below...all you really need is the first few minutes, though the rest is funny, too)
"Whodunnit?" from the UK's "Watch for Cyclists" ad campaign
"Do the Test" - Count the passes by the number of players in white jerseys and test your perceptual skills
The Monkey Business Illusion - Even works for those who have seen illusions like this before! A finalist for 2010 Illusion of the Year!