Via the Ditherati quote-of-the-day mailing list, I read about Putty World in this Wired article.
Basically, they sell Silly-Putty-like goo, but in all kinds of crazy colors. Sure, there's the traditional pink and white, but there’s also shiny silver and even mistletoe. They typically sell it by the 1/4 lb tin, but they offer it by the pound as well.
I put in an order for a tin of Lustrous Bronze and a tin of Gunmetal Graphite. Whee!