Switch/Panic for the Sega CD/PS2 is. in my opinion, the trippiest video game ever created.

This is an example of its gameplay:

http://www.youtube.com/watch?v=-vlhq48JK0g

The game has over 1,000 possible "gags".

A lot of the old Lucasarts 'Point and Click' games had some 'trippy' moments.

Sam & Max Hit the Road
Day of the Tentacle
Monkey Island Series.

Switch/Panic for the Sega CD/PS2 is. in my opinion, the trippiest video game ever created.

This is an example of its gameplay:

http://www.youtube.com/watch?v=-vlhq48JK0g

The game has over 1,000 possible "gags".

http://www.youtube.com/watch?v=GHkBBdyvVnQ

http://www.youtube.com/watch?v=GHkBBdyvVnQ

Ladies and gentlemen, we have a new CHAMPION:

Whatever the f*ck that was!

It's Segare Ijiri... you move the character around and trigger videos and images based on random word combinations you create. The design concept apparently was "devotion to stupidity".

Just looking at art direction though, I like Super Galdelic Hour. It's a minigame collection dressed up like futuristic psychadelic game show:

http://www.youtube.com/watch?v=Dpl-v6ZJQic