How do you convince your retired father into becoming a gamer

Fathers can be the most stubborn people on earth, so don't force it on him. Instead, indirectly introduce video games to him.
1. Start off by thinking of his interests and trying to match a game to it. Try to find a game with a good multiplayer levels. If you don't know what he likes, you can always ask.

2. Play the game around him. If you can, find a (preferably closer to your dad's age) family member to play with you, it helps make games seem more approachable to him. Don't be overly enthusiastic, but try to capture his attention by playing the more spectacular parts of the game around him. After you got his interest, try talking about the most exciting parts of the game to him.

Note: Don't overplay video games around him, you don't want him to think of you as a lazeabout, therefore lowering the credibility of video games in his eyes. Play it three or four times a week, and not for too long of a time either.

3. He should usually be interested enough in the game to ask to play it. If not, gently offer to play with him. If he still refuses, keep on going for a while. Sometimes a person is just strictly anti-video games, but most often he'll indulge your request after a while. And if you chose a good, addictive game that is not to difficult, he should be pretty hooked.

You can always introduce other games after he's comfortable with the first game you gave him, but try to remain in the same genre at first, then branch out.