Every once in awhile, buried amongst boobies and asshats and German women throwing televisions, FARK will link up something genuinely cool. Such is this extended Discover magazine article on Octopus. Summarizing the latest behaivioral findings, it covers things like cognition, play, mischeif, and even perhaps tool use:

Researchers and aquarium attendants tell tales of octopuses that have tormented and outwitted them. Some captive octopuses lie in ambush and spit in their keepers' faces. Others dismantle pumps and block drains, causing costly floods, or flex their arms in order to pop locked lids. Some have been caught sneaking from their tanks at night into other exhibits, gobbling up fish, then sneaking back to their tanks, damp trails along walls and floors giving them away.

Very cool article!