I think this is one of my more favorite underrated episodes of Futurama (I believe it is underrated anyhow, although I am happy to see you guys giving it such high marks). It was the one episode that I could quote in its entirety in my head, which I put to good use during those boring college discussions. Yes, I played this entire episode in my head once. Haha, good times.
I haven't seen this in a while so I will not rate it yet, but I liked everything about it - the physics jokes, the Star Trek sounds, the emergence of Manwich jokes, and especially the whole Fry/Umbriel sequence at the end
One of my favorite lines in the whole series has got to be:
"Why couldn't she have been the other kind of mermaid, with the fish part on top and the lady part on the bottom??"