David After Dentist: Most of us dont regard trips to the dentist as sources of hilarity, but when Davids father picked up his son from the dentist and turned the video camera on, the entire world cracked up and fell in love with the little kid who looked buzzed out of his gourd. Within days, David After Dentist spawned a ton of parodies and mashups. David After Dentist is #3 on the list on the list of the Top 50 YouTube Videos from Time Magazine.
Keyboard Cat: Keyboard Cat actually predates the World Wide Web. This video of a Cool Cat playing a keyboard was created in the early 1980's, but it would take the emergence of the Internet to turn Cool Cat into Keyboard Cat. Keyboard Cat became a harbinger of fail, and whenever you would see him in an internet video, you'd know that something bad and/or hilarious was going to happen. When things went wrong, Keyboard Cat was there to "play them off." It is #8 on the list of Top 50 YouTube Videos from Time Magazine.