Hard to believe that the meme that is! It is a sign of the fast-moving times that these things go from nothing to everywhere to nothing again so quickly! Here are the basics from Wikipedia:
Nyan Cat is the name of a YouTube video uploaded in April 2011, which became an Internet meme. The video merged a Japanese pop song with an animated cartoon cat with the body of a Pop-Tart, flying through space, and leaving a rainbow trail behind it. The video ranked at number 5 on the list of most viewed YouTube videos in 2011.
In honor of the event, casual developer 21st Street Games, makers of the online and iOS game Nyan Cat Adventure are throwing a celebration today!
Thursday, April 5th, 2012 we’re throwing a birthday party for Nyan Cat at 21st Street Games. This event is at 4:30, by invitation only at the studio and available for EVERYONE on USTREAM at http://www.ustream.tv/channel/nyancatadventure. We’ll have cake, a piñata, lots of Nyan Cat Adventure playing, Prguitarman (Chris Torres) in attendance and a special surprise!
Tune in at 4:30pm eastern for a special surprise!
And, of course, here is the original video: