http://www.thinkgeek.com/product/abd4/ (out of stock)
Which reminds me of a story …
The astronomy professor just completed her lecture on the life cycle of the sun and had commented that the latest theories suggested that the Sun would run out of hydrogen in 2.8 billion years, killing all life on Earth.
A hand frantically waved in the back of the lecture hall.
“Question?” the professor asked.
“How much longer until the sun runs out of hydrogen?”
“Approximately 3 billion years.”
“Oh thank god,” the student uttered in obvious relief. “I thought you said million years.”