I really like the atmosphere and the way the world looks like in Day of the tentacle (and Psychonauts, etc.). It's kind of wacky. So I was wondering what other games, old or new, are there that have the same sort of graphical outlooks?
I asked this in underdogs as well but they haven't given too many answers yet.

Well, you can try Maniac Mansion. It's kind of part one of DOTT.

I don't know how DOTT and Psyconauts (sp?) have similar graphics, but there are a few that have wacky graphics.
Darwinia, SWINE (which was just released for free!!!!), Big Red Racing, Little Big Adventure, Normality, Virus 2000, that is what comes to my mind right now.

There is an amateur adventure called No-Action Jackson:

http://www.talesofinterest.com/no-action/

practicaly any adventure from LucasArts...