The live band onstage -- jacked in from a studio in Prague -- isn't very good, so I duck into the back room where there are virtual racks full of tapes you can sample, listening to a few seconds from each song. If you like it, you can download the whole album, with optional interactive liner notes, videos and sheet music.

I'm pawing through one of these racks when I sense another avatar, something big and shaggy, sidling up next to me. It mumbles something; I ignore it. A magisterial throat-clearing noise rumbles in the subwoofer, crackles in the surround speakers, punches through cleanly on the center channel above the screen. I turn and look: it's a heavy-set creature wearing a T shirt emblazoned with a logo HACKERS 1111. It has very long scythe-like claws, which it uses to grip a hot-pink cylinder. It's much better drawn than Raster; almost Disney-quality.

The sloth speaks: "537,824,167,720."

"Hey!" I shout. "Who the hell are you?" It lifts the pink cylinder to its lips and drinks. It's a can of Jolt. "Where'd you get that number?" I demand. "It's supposed to be a secret."

"The key is under the doormat," the sloth says, then turns around and walks out of the club.

My 15-minute break is over, so I have to ponder the meaning of this through the rest of my shift. Then, I drag myself up out of the couch, open the front door and peel up the doormat.

Sure enough, someone has stuck an envelope under there. Inside is a sheet of paper with a number on it, written in hexadecimal notation, which is what computer people use: 0A56 7781 6BE2 2004 89FF 9001 C782 -- and so on for about five lines.