Model Builder is perhaps the ultimate niche game. Its a simulation of, wait for it, model building. By this, I meant it’s precisely what it says it is. You take the simulated model out of the simulated box, simulate preparing the simulated parts. On this is done, you arrange these parts into the proper order, you move on to simulating the assembling, gluing and painting of the model. When finished, you can place your new simulated model on a simulated shelf, so you can admire it for all time, or until your hard drive crashes anyway. So if you find simulating stimulating, (see what I did there?) come along while we check out Model Builder.
Source: N4G PC Model Builder Preview (The Gamers Lounge)