Games still pay the bills. But Tuesdays and Saturdays are rocket days. As the leader of Armadillo Aerospace, Carmack has been involved in the chase for the X-Prize, a $10 million bounty promised to the first amateur team that builds and flies a manned craft into space. Winning the prize is pretty much out of the question now, particularly after an Aug 7 crash that completely destroyed the team's vehicle. ("It's a good thing Doom 3 is selling very well..." cracked Carmack on the team's Website after the crash.) But Armadillo plans to see its work through to completion regardless.

You see, instead of being frustrated with the crash, Armadillo is excited. Failures, especially catastrophic ones, explains Carmack, allow industries to approach things from a different angle – which can result in tremendous advances.

"One of the reasons microcomputers progressed so fast is people are willing to accept crashes," he said. "It's faster to build something and try it even if it means you'll have to rebuild later. ... If you spent too much time building and massaging one vehicle, you don't learn anything."