(Created this so I no longer have to post this in every thread someone creates every time the GameSpy Halo Lobby is down! ::) )
NOTICE: The Halo GameSpy Lobby is UNRELIABLE and may be inactive - or even GONE! - at ANY TIME.
GameSpy's agreement with Microsoft (the owner of the game, NOT Bungie!) was up over a year ago and has been running without attention or maintenance for some time. It only remains up as long as some nice soul there decides to leave it up!
P.S. ...And Micro$oft has no interest in keeping the Halo PC stuff up,
since they'd rather you used their proprietary Live! system(s)!.... :bang: