An abbreviated list...
High school "games:"
The obligatory single player tic tac toe (with C and not java, so I ended up taking a 15% deduction for not following directions
) that everyone seems to have programmed in their intro to programming class; Go Fish! card game for the IBO that used C++
Single player chess game that was the final project for an AI class I took in college using java (not by choice!), a two player Go! game I made for my game theory professor because he was always complaining about us students losing his black and white game pieces whenever we played in class
Simple pac man clone I made while learning pygame libraries and reviewing python, and various games with pygame incorporating hacked wiimote controllers targetted at children with physical and mental disabilities (which was challenging and fun to do, but the games themselves aren't much fun to play for most people. The kids loved them though), tended to be one or two player racing games or silly "fill up this meter faster than your opponent so your avatar can do something funny like throw a pie/dump a bucket of water on your opponent's avatar." Hard part was in programming the movements and getting things to register correctly, not so much the actual "game."
Currently working on a typing game using pygame (or should I use something else?) aimed at secondary school kids that also deals with HIV/AIDs (two birds with one stone--computer literacy and HIV education, both big problems in Tanzania) with some of my students so they can learn how to program.