The Kingdom of Loathing (or KoL, as it has come to be known by its player base) is a free, comical RPG, brought to you by the folks at Asymmetric Publications.
KoL is currently in open beta -- it's open to the public to play, but it's not quite finished.
KoL is played from the comfort of your browser, and is adorned with a staggering array of stunning hand-drawn images. It is turn-based, which means you get a certain number of turns (Adventures) each day.