Wumpus Game
This is an online version of the 1972 game "Hunt the Wumpus", with in-game agent programming capabilities (but no server to store your changes - Sorry!). This work has been inspired by the book Artificial Intelligence: A Modern Approach, which uses the Wumpus world in many of its examples.
WARNING: This was my first attempt at rich browser applications.
Other
Also feel free to check out NoGap, a simple RPC Framework for simplifying browser <-> Node interaction.