It's a functional programming thing; stands for "Haskell Time To Party". It might sound funny, but it is very, very serious and esoteric.
This week a coworker and I (more than 10 years of admin experience each) spent 15 minutes wondering why one internal web server was not reachable from a specific computer. Turned out that we got so used working with Firefox and Chrome that we forgot IE8 doesn't understand an address like IP:port/ if you don't specify the protocol (http://IP:port/).
As the Zen of Python says, explicit is better than implicit.
As my fingers say, thanks for the reduced keystrokes.