My main game is a 1 on 1 I play with my 7yo using an adaptation of the D&D Rules Cyclopedia (edit: I just realized I already responded to this thread days ago. Oh well).
The campaign started as just the kid playing, but at their insistence I made a PC of my own as well about 8 months ago.
Yesterday was the climax of a fairly long string of adventures, which started using Basic Fantasy RPG adventures (and that game system, as well, until I felt the kid had mastered it well enough to move on to the RC). I'd been using the Top Ballista supplement to link adventures together for a while, including B4: The Lost City, I1: Dwellers of the Forbidden City, and the BFRPG adventure Monkey Isle. We'd been retrieving various relics and magical items for Haydrech, a nagpa necromancer from Serraine, but my 7yo became very suspicious of Haydrech's motives after we watched The Dark Crystal a few weeks ago.
So upon returning to Serraine with the golden idol we fetched from Monkey Isle, we were stopped by someone who asked us to spy on Haydrech for them (this was the beginning of the Heart of Darkness adventure from Top Ballista). We snuck into Haydrech's compound to gather information, but overheard through a door that Haydrech was planning to overrun the world with zombies, starting with the mongai (a term I used rather than "mongrelman") tribe the kid had liberated from the Forbidden City upon becoming a Barbarian Lord.
Side note: don't ever underesitimate the importance of Name Level to a 7yo.
Anyway, spying plans went out the window and my 7yo's character kicked in the door. In the ensuing battle we mowed easily through a bunch of mooks but Haydrech escaped through a secret door that led to a landing bay on the edge of Serraine, through a long tunnel. Haydrech had taken off in a magical flying canoe, but luckily my 7yo had a Broom of Flying (picked up from random treasure a while back) and gave pursuit.
Folks, that chase was epic. Haydrech was casting Magic Missile, Cone of Cold, whatever and the kid's barbarian just kept coming. Jumping onto the canoe, the kid's character raised his Flame Tongue greatsword above his head and brought it down mightily upon the nagpa.
He missed. Twice. Meanwhile, Haydrech coated the surface of the canoe with a Grease spell and did a barrel roll. Luckily, the kid's character has a Strength of 19 thanks to a magic bracelet he retrieved in one of his first adventures and managed to hang on.
At this point the barbarian was literally down to 2 hit points, but knew that the nagpa had to be down really low as well. Understanding that one more missed attack would probably mean the character's death, the kid made one last attack, rolled the dice, and sweated a little.
It was a natural 20. The nagpa's last 8 hp went bye-bye, and you can bet my kid will be telling this story to EVERYBODY for a long time.
There's nothing like the feeling when the dice finally roll your way at the perfect moment.
Whew. That was long-winded. But, I hope, with the read.