Jerome Etienne shared Game Workshop: Let's Do a Fighting Spaceship Minigame Together -- a talk about building a little game with three.js and the Web Audio API. It includes slides, a video of the talk, and a demo.
As you move it displays your position on a map, and also shows the longitude and latitude. Therefore, your challenge (should you choose to accept it), is to get to the top of Olympus Mons!
The rendering style makes it look a little bit like Minecraft, and one of the author's ideas sounds like an amazingly interesting take on that genre:
a science-based (no dragons) survival mode on which you have to generate your oxygen and fuel, extract your water, grow your food, make martian bricks, etc
The particle simulation is running on the GPU to handle 262,144 particles in real time. It's a pretty standard technique these days, but it could be helpful as a reference for some. No three.js, just modules.
If you look at the source you'll see how shaders can be used to create interesting particle effects.