So I introduced Owen to TF2. Before doing so, I installed some modified graphics files that convert the game in to the German censored version. There is no blood (even on the weapons) and the characters explode with confetti or gears/springs when they die instead of body parts flying around. (add -sillygibs to your start up line to see em).
I have him a run through of the game mechanics and he already knew how to move from playing Minecraft. I let him explore all the classes in a 1v1 game with me and he quickly stuck with the Scout due to the movement speed. He was bent on playing a game "with all your friends, Daddy" which he is very much not ready for yet but we did try some training with bots.
This time he made Daddy even more proud, and played the Heavy the entire time.
After a few rounds of playing on his own, he produced this awesome scoreboard at the end of a victorious round. Little bugger even understood the process of standing on the control point to prevent the other team from capturing it and he rarely left his post unless he had to get ammo. After a short while, I heard more and more `dings` and some domination and revenge sound effects.
(http://i.imgur.com/6bgxs.jpg)
I left the room to take a leak and heard him shout "I'M INVINCIBLE!" and came back to see him Uber'd. :)