I implemented a particle-based liquid simulation with gravity, viscosity, pressure, and surface tension. The particles are simply depth-tested point sprites where the edges are discarded.
Initial liquid
Settled liquid
Clumping due to surface tension
I also simulated liquids with different densities interacting. I put a more dense liquid in with water and the two naturally separated.
Initial state with two liquids
Two settled liquids
Force applied to two liquids