For almost 20 years, my family and I have been good friends with our neighbors across the street, the Becker’s, who have two sons: Nathan (19) and Dylan (18). The “Becker Boys” are ardent video gamers, and last year, got into 40K, with Nate choosing Space Marines, and Dylan picking up Space Wolves.
In teaching them how to play, we did two demo games against Necrons, then a “for-real” match against my proxied-Tyranids, then a massive contest with lots of figures and vehicles on each side.
The boys went off to school in the fall and played a little bit while they were away. On Christmas break, they came back and we did a holiday-themed game.