Trans-Siberian Railway Egg, 1900. Presented by Nicholas II to Czarina Alexandra Fyodorovna. Platinum, tinted gold, silver, diamonds, rubies, onyx, rock crystal, wood, silk, velvet. Kept in Kremlin Armoury Museum, Moscow.
Aluminum engine block coffee table. Nice pistons raise up glass. This is actually pretty cheap and easy to make if you can find a good block at your local junkyard. The most expensive part is the tempered glass.