First computer wargame - East Front by Chris Crawford
First non-wargamers wargame - Risk
First real-wargamers wargme - Tactics II
First miniatures wargame - one my brother and I "invented" before we knew there was such a thing... we called it, interestingly enough, "war". We had a huge hard canvas tarp (10' x 6' or so) in the basement and we'd pile junk under it, creating hills and valleys. We'd then pick a side of the battlefield/canvas and deploy our 1/72 unpainted troops that we bought with our meager allowances. It made for interesting match ups as the local hobby store had a very limited selection of soldiers. One of us would have a nice mix of Japanese soldiers and American Marines and the other would have U.S. Civil War cavalry and German Afrika Korps infantry. We'd then take turns moving the guys around, a few inches for each soldier, and then you were allowed to "shoot" a certain number of times with a ping pong ball... if an enemy guy fell he was dead. The carcasses had to stay on the battlefield to simulate reality.... ah, those were the days!
First naval miniatures wargame - another brilliant invention of mine... we'd take the models that I'd spent hours building and duke it out. I had probably 40-50 ships and we'd each pick one out and stand about 20 yards apart and begin firing... to simulate "firing" we'd throw darts at each others ships. Pieces would fly off upon impact and we'd laugh like hell... when you were luck enough to get a critical hit (i.e. the dart stuck in the ship) you were allowed to pour model cement over the hole and you could put a match to it for a certain amount of time. The owner of the ship had to sit idly by for that time and then, after that time, he could put it out. You could not use water though, you had to blow it out... man was that fun! I can still see us laughing so hard that you couldn't blow out the fire and the whole ship would be a black hulk by the time it was over! Such fun...