There were plenty of games of Mastermind along the way, and mindless hours playing Yahtzee.
Steve Jackson Games had "microgames" which were really cheap and fun as wargames - anyone play Ogre or GEV?
This bequeathment also included a pamphlet by SJ titled GAME DESIGN: Volume 1: Theory and Practice It's a fun read. It ranges from discusion of hex vs. grid in war games, and pushes his generic philosophy for RPGs that underpins GURPS. It was written in 1981.
I also remember 'Cheap Ass Games' at the local friendly gaming shop. We bought them more than we played them.
Monopoly but no one ever won/lost because the bank was very generous with loans.
We were also pretty good at building houses of cards, which is especially fun when the surface you're building on is a fucking boat.