Since September an internet user "webdrivertorso" has uploaded over 77,000 eleven second videos of colored rectangles and musical tones. So far no one is sure who is doing it or why.
BBC News - Webdriver Torso YouTube mystery clips' French connection
There is also someone posting videos on youtube that consist of a little electronic jingle, then a woman reciting a series of numbers. Speculation is that it is a modern incarnation of the WWII "numbers stations" where spies sent each other messages by short wave radio that consisted of a coded series of numbers.