I made a few in high school, first for a class exercise and then for every assignment after that whenever I could convince my teachers to accept it. Mostly colourful strategy games, plus one Waterloo war game for history class (took days to make all the tiny little horsies).
In uni we made and played a lot of 1000 Blank White Cards and Nomic-type stuff. My favourite deck was called Alien vs Predator vs Johnny 5, in which you have a team of three characters who can each use different item and ability cards to attack other players' characters provided they're still 'alive'. I've been meaning to scan it for years.
I designed a complex evolution-themed strategy board game there too, but never finished cutting out all the little bits. One day.
Recently I made a couple of games for teaching English to little kids.
One's a super cool dungeon crawling game where players explore a dungeon which is generated by drawing different corridors from a stack and laying them on the floor. Some rooms are special and may contain traps and/or some dungeon feature or a random amount of loot (letter cards or useful magic items) and might be guarded by a monster which must be defeated by spelling, scrabble-style using your letter cards, an English word at least as long as the monster's name. Basically I slapped
Sorcerer's Cave and
Dungeon Scroll together and took credit.
The other's a tense luck-pushing game about pearl diving (because all I had for counters were white go stones) with a fun competitive Scattergoriesish element that lets kids fuck with each other.
Unfortunately my bitch ex-housemate kept them both for her babysitting business when I moved. I'd go get them, but I figure at least with her some kids'll get to enjoy them.
Somewhere around here I've got a half-finished game about gods (players) screwing with a developing civilization for fun. Thanks for reminding me. It has a neat mechanic which might even be original.