My vulcano simuation for the very popular TV show COSMOS: A Spacetime Odyssey with Neil DeGrasse Tyson (nominated for an EMMY).
The most challenging part was the fact that the simulation is roughly 1500 frames long (!) and had to move very slowly while maintaining detail. Not the easiest of tasks! The final sims was retimed in FumeFX by 200% which caused a few flicker headaches. It is not really designed to retime that much. The fume grid was pretty massive in size as well and used around 12-16gb of ram.