Fluxx 4.0 is the most recent release of the original hit card game with ever changing rules!
From the manufacturer's website:
It starts out simple, with just the Basic Rule card: draw one card and play one card during each player's turn. But New Rule cards quickly make things chaotic. Even the object of the game will often change as you play, as players swap out one Goal card for another. Can you get the Rocket to the Moon before someone changes the goal to Death by Chocolate?