Joints:
Would attach two bricks together, but be free and could move in any direction.
Hinges:
Would attach two bricks together, but be locked on an axis.
Motors:
When a brick is placed on top of a motor, it will spin. Speed and direction could be changed through events.
Before any of you scream "OMG U GOT DIS IDEA FRUM ROBLOX!!!!!1", I would like to point out that just because ROBLOX has it doesn't mean it was their idea to begin with.