Day of the Tentacle (Lucasarts, 1993) is a beautiful and unsurpassed adventure game created by the Tim Schafer and Dave Grossman with a little help from Ron Gilbert. It also happens to be the sequel to Gilbert's groundbreaking Maniac Mansion. Though the game itself isn't particularly rare, its triangular toblerone-shaped boxed version -the one you see above- has been known to sell for over 500$. It's rare. And beautiful. Also, I own a copy which I adore, though you too dear friends can follow the link to this Day of the Tentacle auction and join our happy club. Seller ships worldwide.