Head to the crashed vertibird located at the south of the map, in about the middle. This will require two companions and tons of firepower, or several stealth boys and a high sneak skill. The crash is surrounded by hardened Sentrybots and hardened Mister Gutsies who are hostile towards you. Inside the wreck are some of skeletons and a Tesla Cannon with orange electricity inside (the core is orange). It has an after-effect of damage for awhile after being fired. Test it on the robots or the ghouls from the nearby nuclear crater.