Well, you could play frisbee or hide and seek, but unfortunately you need a gamertag to even play offline. I don't know if you can still recover a gamertag on a regular Xbox, but if you can, have a free silver tag set up on a 360 and recover it on the old Xbox.
--- It's not those that can inflict the most, but those that can suffer the most who will conquer.
I just tried my PSO without it connected to my router. You have to have an original xbox and have your xbl account on it as well. I didn't even sighn in because well you can't. BUT IT WORKS! Its free to play it offline. :D Play it offline. :D Have fun. Back to playing my level 80 caster.