I just bought the orange box and was wondering: is there any possible way to play the game offline and with only one player? Is there anyway to make computer controlled players at all? If not...I still have portal and the half lifes....sigh.

No, TF2 is a multiplayer game.

kind of wish there were some sort of single player mode. the characters are pretty neat, i wouldnt mind seeing some kind of story

They have considered making a TF2 movie or something?

Anyways, on the PC versions you can make custom maps that only require one player, but those really don't do much and aren't very fun compared to multiplayer? PC version is the way to go, definitely, if you want TF2? Especially since updates and all I think?

It would just end up like the old UNREAL tournament games, you'd get some goofy ass story in the cinematics and dethmatches with bots.
Not exactly a single player campaign.

Valve has both TF2 cartoons and comic books in development. Gabe Newell has said the comics are more likely to materialize than the cartoons, though he also talked about hybridizing the ideas and doing motion comics.