Fluid Simulation using Nape and Thresholding

Move mouse to move fluid source position.
Spacebar to toggle debug mode.

Using the Nape Physics Engine to model particle collisions, blurring the particles and thresholding the result you can put together a half-decent fluid simulation. It won't score any points for realism, but for an extremely easy gimmick to implement it works quite well. The effect feels similar to the Flash game Spewer.