They're either in my shelf, computer, or in parts unknown...
SaM Hit the road
SaM episodics
MM: Day of the Tentacle
Most of the Humongous Entertainment games (although i've misplaced them all)
Escape from Monkey Island
Dreamfall 2: longest journey
Some horror games, I guess (Silent hills 1, 3, 4, and origins)
Games I downloaded from Adventure Game Studio (especially the Chzo Mythos games, those are awesome)
Every Leisure Suit Larry games, only played 1st, 5th, and 7th.
Psychonauts (of course)
Beyond good and evil (Ubisoft rules!)
Nick Bounty games
Brain Hotel
Oddworld games (Oddworld rules!)
The Neverhood (Doug TenNapel rules!)
That game based on "from earth to the moon" (forgot the title)
Peasant's Quest (awesome game, but we didn't get to kill Trogdor

)
That Rugrats adventure game for the PC (long gone, though)
still looking for Grim Fandango...