So both kids will be Game Mastering for their Birthday parties this sunday (their birthdays are only 12 days apart and they're still willing to share celebrations).
I've been working on a streamlined ruleset inspired by DnD for them to work with.
Essentially the Abilities are:
The basic mechanic will be to roll a D20 equal to above your Ability score. I don't think I'm going to work with skills.
I've run games for kids many times, I'm not trying to dumb the system down, just make it easier for both of my kids to run, since they'll be sharing me as a resource.
Right now the Classes are:
Weapon Master - Always does 12 (using flat damage) damage, no matter what weapon.
Martial Artist - If their successful attack roll is even, they Punch for 6 damage; if it's odd, they Kick for 8 damage.
Barbarian - Normal damage is 8. Can get Angry 3 x Day and Roll D20 + D6 when attacking and do 10 damage.
Knight - Fighting Damage is 6; Takes half damage from any successful attack roll.
Archer - Bow Damage is 10, Crit on an 18-20; all other weapons do 4 damage.
Thief - Weapon damage is 5, Crit on 15-20 for 15 damage.
Holy Warrior - Weapon damage is 6; Can Turn Undead by rolling an Even number, if the number rolled is also higher than Judgement the Undead is destroyed; Healing Aura of 3 points for any ally who is less than 1/2 Hit Points.
Witch - Magic Damage of 8; Cast spell by rolling higher than Brains; weapon damage is 3.
Druid - Weapon Damage is 5; can take an animal form where damage is 9; Cast spell by rolling higher than Judgement.
Bard - Spell Song hits 1d6 enemies for 6; Weapon damage is 4; Can cast 1 x Battle by rolling higher than Cool.
That's the breakdown, right now.