Wendland TD is a German Tower Defense like game. In this game, the player's goal is to stop a truck or train (you can choose between a street or rails in the main menu) by placing obstacles like garbage, cows, or other trucks on the road/rails. This game is only available in German, because it is related to events that are actually happening like this in Germany.
Five Hundred is a card game for four players similar to Euchre or Bridge, especially popular in Australia and New Zealand. The wikipedia page has a comprehensive description of gameplay. This version is implemented in C++/Qt. It incorporates graphics from the svg-cards project. Computer players are scriptable in Lua.