There are a few really, really simple card games out there. War - Flip a card. The higher number wins. Only when a tie occurs does anything more happen. Go Fish - Do you have a nine? No. Go fish. Take one from the pile. Dead easy. Old Maid - Take a card from another player. If you make a set, play them down. The player with the old maid at the end loses. Easy peasy. I’m sure there are others that are just as easy, but these 3 first come to mind.