i was driving home from class and when merging onto the freeway the car started making really bad fpfpffpfpffpp noises. made it to gas station and popped the hood. the #1 (first one on drivers side farthest from fire wall) popped out and was still in the plug wire. borrowed a socket from service station and put plug in but it wouldn't tighten. plug was not stripped so i am guessing the ______ (whatever you screw the plug into is called) is stripped.

1). what do i do? can it be rethreaded?
2) how bad is it to drive on 7 cylinders if only for a mile or less?

 

I would imagine the spark plug hole is stripped. Since is the #1 hole, you might have enough room to have it heli-coiled with the head still on the car.
Driving it for a mile may not hurt anything, but I would avoid it if possible. Since there will be no heat generated from combustion, the valves should be ok. It will definitely make a racket. If you don't want to take the risk, don't drive it.

 

what is heli-coiling? same as re-threading?? is it expensive?

 

It is a thread insert. The hole is tapped to an oversize and the insert screwed in. The new threads will be tougher than the original ones. Search the 'net for helicoil to get some info.

 

The exact same thing happened to me. Same cylinder, even. I had to have the cylinder head removed and have the spark plug repaired with a threaded insert like Shoebox described. It wasn't cheap.
It's not likely you did any damage by driving a short distance with a missing spark plug.