Gravity is a game not unlike Worms or Angry Birds. Two players take turns hurling missiles at each other. The twist is that the missiles must travel through (or round) a solar system, where each planet exerts its own gravitational pull.
3Doku is a 3D version of sudoku. (Well, OK, it is a 2D version of sudoku wrapped around a 4×4×4 cube.)
4tris is a version of Connect 4 with added havoc caused by lines vanishing and forming combos.
Analogue Snake is the classic phone game Snake with all the right angles taken out.
Explore the Mandelbrot Set with the HTML5 canvas element.
Explore Koch snowflake curves with the HTML5 canvas element.