My buddy and I did a mock up "three gun" course one time that was a blast. Start with pistol in holster with 8rds in mag, empty chamber, four targets (8.5x11 piece of paper on cardboard backed target stand at different distances, on command "threat" time starts, draw, rack slide, two rds per target in order closest to farthest with having to sidestep or lean to shoot the fourth hiding behind one of the other three. Drop slide (held open from last rd), re-holster on way to pick up shotgun (pump in our case) loaded with two shells, fire one at a paper target, upon hearing the shot a buddy throws a clay, fire at clay, open action set shotgun down, (this is all in front of the rifle range line had the place to ourselves). Run around into rifle line and pick up our bolt action .308 w/4 rds in the mag. Four 8.5x11 paper targets at 100yards with a 4-5inch orange circle in the middle of each page. One shot per target, open bolt, gun down hands up time stops. Scoring by time: pistol +0 sec for hits on page, +2 sec for missing page but hitting cardboard. Shotgun +5 sec for missing page, +5 sec for missing clay (assuming a good throw), rifle +0 for hitting orange, +2 sec for hitting page outside of orange, +5 sec for missing page.
Total time, add 'penalties' = score. Lowest score wins. It was SO much fun. Unfortunately due to ammo shortage we only ran the course twice each but still had a lot of fun. Did incredibly well for never having competed in anything like this before.