My Favorite Board Games and How I Play Them
jimwestergren.com
jimwestergren.com
Lately I'm playing a lot of RPGs solo and with my kids. One-pagers have been a hit with them. Someone posted a bunch of free examples here:
Edit: Since you mentioned The Space War, one space wargame I enjoyed reading recently (haven't yet played) was Star Strike. It's from a company that made an RPG called Space Master. They built in three different modes of play, from beginner to advanced, with a few gameplay scenarios for each level. You can keep it simple or literally bust out the Pythagorean theorem for use in combat maneuvers.