Golems

Everything About Fiction You Never Wanted to Know.
Build Anything.
Official motto

Golems is a free "3d recreational physics simulator." It's designed to be remarkably intuitive and user-friendly -- basically, you can do anything, from something as simple as dragging a few blocks and motors to make a crude car to something as complicated as giant robots, hovertanks, or fully-functioning vending machines. Machines can be user-controlled or, with a bit more effort and some sensors, pilot themselves. It's a bit like LEGO, but the laser cannons work and you never run out of bricks. The physics simulation is also surprisingly accurate and realistic (with the exception of a few obvious impossibilities, such as the aforementioned lasers). Best of all, it's fun.

You can download the game here, and see the forum (where other users upload their machines and give tons of useful help) here [dead link].

Not to be confused with the mythological creature from which it derives its name.

Tropes used in Golems include: