The latest newsletter from Industry trade publication CTW has vague word of the possibility that Half-Life 2 will be appearing sooner than would be expected, considering the game hasn't ever even be officially announced. Here is what they had to report:

Half Life 2 in 2002?

The sequel to possibly the greatest game ever made - Half Life - is rumoured to be just six months away from completion, a senior US source revealed this week.

As just noted, Half-Life 2 has not actually been officially announced (story), and CTW's blurb admits this is a rumor (or rumour as they put it in the Queen's English), so keep your salt shaker handy in case this requires more than a grain of salt to digest.