I have an idea. :O
We could create object models, and turn them into vehicles similar to the ball or weighted cube, and you could move them around with the Gravity Gun.
Examples:
Cinder Block
Cardboard Box
Computer box? :D
Ordinary box, for stacking
A blocko brick, for display or throwing at people
Etc.
I also had the idea of having a 1x2 brick as a weapon, and you can throw it at people. :D
Feedback please.