Since there is shockingly little here, Jumlian will fill in the rest, having been (still is, I think, technically) a member of college... but the info may be a little (4 years) out of date
Fitz, as it is often abbreviated, seen from the front fits into the second-most-famous category of Cambridge college architecture, that of carbuncle, or eyesore. While NewHall is often unfavourably compared to a hospital, Fitzwilliam is most similar to a multi-storey car park (in old court anyway), with the dark bricks, three floors and small windows. The college is famous - to its members, anyway - for the strange oddity that is the main college hall. The flashing coloured lights of college entz seen through the huge windows at the top often led people to call the police saying that there was a UFO landing in the college grounds.
Fitz doesn't really get visitors, being largely an architectural atrocity. This is not to say that it has the monopoly on architectural evil - the typewriter of Christ's is worse, just smaller. We do get a few visitors to the new court of Fitzwilliam, which actually looks a lot more pleasant. It is designed in a Japanese style and was rather nice, I recall. Occasionally you do get a Japanese architect / tourist wandering around in summer, but not too often.
We used to have a CollegeCat, I think it was called Sprocket. It was quite friendly and liked sleeping on the photocopier (until someone photocopied it) and had nominally the same powers and privileges as the college Dean. Allegedly. I think it died just after I left, though, and we got invaded by the NewHall critter (a nasty piece of work).
Sprocket's memory used to live on in the form of the academic file server, though that has also since passed away. Sprocket was IIRC replaced by a cat called Holly, whom I have not seen for, erm, years. NewHall/Sam skulked the grounds until his tragic demise, but putatively spent most of his time in his host's development office. As for Sprocket's alleged equivalence to the Dean, that has given me worrying mental images of committee meetings being chaired by a cat. *shudder*