I just did one saturday, had a 3" stainless drywall screw in the tread. Took it to my friends shop, dismounted it, used an air grinder to rough up the inside surface, wiped it down with glue, stuck a patch on it [looks like a 5" wide thumbtack only rubber with a rubber stick on it encased in metal], pulled it thru, rollered it down on the backside, remounted the tire, inflated, set it to 40psi, stuck it on the balancing machine and balanced it, took me about 15 min.
If you use a plug like suggested above, take a drill bit in a drill and drill the hole out, you want to break any belts that go thru the hole otherwise they can rebound, puncture and let air out. This is my third in two summer, $#$% contractors, ought to be a legal requirement to clean any loose pointy things off the work truck before leaving the job site..