Quizzley is a simple site that allows you to create a quiz or a poll and distribute it to your audience. Once your audience pairs with the quiz/poll, their smartphone will automatically transform into the voting pad. It's a fast way to interact with your audience; no authentication or registration are needed.
Project shyknight is a classic-style platforms game like Manic Miner and some others from early 80s. It has very nice and polished, colorful retro graphics, and simple but addictive gameplay. Eric is in love with a greedy girl named Martina. He must collect all the items she wants to make her happy.
QMentat helps you practice mental arithmetic. It uses arbitrary-length fixed point arithmetic, and can handle any size numbers, only limited by the size of your screen (and in the case of division with an integer result, the speed at which the number can be factored). It is also quite configurable, allowing you to tailor the questions to your needs.
Galois is a computer game of the "falling blocks" type, but with unique features. Unlike most other games of that type, it is not limited to blocks made of four two-dimensional, square bricks: you can choose among several different brick shapes, blocks composed of more or fewer bricks, and even between two- and three-dimensional games.