Egg shoot: think precision rifle at distances and the target is an egg.
As for IDPA, it's an action pistol competition. Usually there are several different scenarios presented that represent some sort of defensive shooting situation (you get attacked at an ATM machine or someone breaks into your home, etc) or a test of skills that would be required in defensive shooting (such as shooting w/ a flashlight). Equipment is basic. Essentially a stock handgun (there are 5 different divisions based on the type of gun you use), a carry holster of some sort (no competition grade stuff allowed) and magazine holders, a concealment garment of some sort (vest, windbreaker, etc). Each timeD string of fire can not require more than 18 rounds so it's not a reloading event and you can get by with 3 magazines or speed loaders.
GOAL, as well as some local clubs, have intro programs. It's great to attend one of these, but not necessary. Show up at a local match some day with your stuff and try it out (just make sure it's a regular match and not some sort of sanctioned/championship level match - that's not a good time to learn and the match staff won't be able to spend much time with you). Just let the match director know you're new to shooting IDPA and they will give you the run down on the safety rules and some of the other basic rules. Try it and have fun.
As for what type of gun? Use what ever you have that's a basic/stock gun.
Stock Service Pistol: Glock, Sig, S&W, Berretta (double action semi's)
Enhanced Service Pistol: Browning High-power (single action semi's, non-45 cal)
Custom Defensive Pistol: 1911's (single action semi's, 45 caliber)
Stock Service revolver: 4" or less revo that loads with speed loaders
Enhanced Service Revolver: 4" or less revo that loads with moon-clips
You don't need anything fancy. Some of the best IDPA shooters in the world use a Glock (G17, G34, G22, G35).
Good luck and have fun.
