Octopuses are highly intelligent and probably more intelligent than any other invertebrates. The exact extent of their intelligence and learning capability is much debated among biologists but maze and problem-solving experiments have shown that they do have both short- and long-term memory. Observe this
Link: Google Video
When you actually use the word octopi you use it wrong.
Octopus=Singular
Octopi=Plural
Indeed these animals are amazing. Great video.
Octopus is a word of Greek origin ("eight feet"). The correct plural, based on Greek, would be Octopodes (pod or pous is the singular, podes is the plural).
If you want to treat it like an English word, just use the standard +(e)s, making Octopuses.
Changing the -us to -i is treating it like it's a Latin word, which it ain't. It's trying to sound pretentious when it's really just misinformed.
I think the video is cool. It doesn't prove intelligence by any means, but it was nifty to watch.
Someone answer. :S
This video crept me out. :|