What's that one adventure game you can just boot up and have a great chill time with? Mine would probably be Day of the Tentacle. It's such a wonderful, colorful world to inhabit, and all the characters are lively and oozing with personality (no Sludge-o-Matic pun intended). I could spend hours just walking around talking to characters and not even think about solving any puzzles.
What's the one game you'd boot up to just relax with?
The Sam and Max games scratch that itch for me. If I'm in a funk and don't have the energy to play a new thing, I can fire up one of those games and have a laugh for a while without even thinking about whether I'm going to finish this particular playthrough. They're the very best kind of absurd in everything from the art to the dialog to the puzzle solutions!