Yesterday, Bellevue's Valve Software quietly updated one of its ancient games, the bizarre, award-winning Portal. Valve's updater typically includes explanations for changes ("fixed bug," "added weapon," etc.), but this update note was noticeably short and cryptic: "Changed radio transmission frequency to comply with federal and state spectrum management regulations." Um. Huh?

When fans started rifling through the game's updated files, they found more weird things: blurry photos; Morse code sequences; a phone number in Kirkland, WA, that makes modem squawks when called. Fans then connected to that phone line with dial-up modems. The story only gets weirder from there, complete with strange bits of computer art and long-winded essays from in-game characters:

Frail, brittle hands make holding science devices difficult. Most were born before the advent of science, and can become confused and disoriented when asked to participate in relatively simple tests (teleportation, invisibility, adjusting esteem levels of orphan children).

Valve has run its fair share of viral promotions—in one, fans who wrote to a hidden mailing address received a response from a fictitious weapons dealer—but this is the company's most remarkable trip down the rabbit hole yet. I've asked reps from Valve if this is a hint to their next big game announcement. Portal 2, hopefully? I'll also be on hand at next week's Game Developers Conference in San Francisco, where I'll corner any Valve staffers I see for info.