The 7th Guest DYK

[Xannidel]

At the very beginning on the Ouija board, type "Zaphod Beeblebrox" EXACTLY! You need both words capitalized and the space. You'll hear an echoing voice say "GROOVY!". When you bring the cursor to the corner of the board you'll see chattering teeth, click. Click on the area you want to go to.

While you get this "open house" mode by beating the game, this reference to an AWESOME book series is still too good pass up.

References:
http://www.ign.com/cheats/games/the-7th-guest-pc-6310
http://www.mobygames.com/game/7th-guest/trivia
http://en.wikipedia.org/wiki/Zaphod_Beeblebrox (near the bottom in the Cultural References)