This mod allows you to merge movable objects, such as crates, containers, and forklifts, with vehicles and drive them around. Download for the mod and map in the description; neither are made by me.
I think this is a little bit late, but it's an interesting mod nonetheless. Has something to do with tagging two objects (one drivable and the other the thing you want to drive) together. Hence the mongoose crate. Quite lolzworthy
It uses what's referred to as "parent" & "child" labels... Parent - This is the primary object (typically a vehicle). Child - This is what attaches to the primary object. There's a gametype called "Space Wars: Battle" (Gametype & Map Varient) which uses these labels to create space ships.
Wow....I just came on here for the first time in years and saw this post(and signed up just to reply!). I never realized how popular the mini-game I made would be. But yes, the space ships are a perfect example of what can be done with parent/child. You can actually make the parent also as a weapon, AA, etc. and create other wacky things(Attaching a soccer ball at the right angle to an AA can create a soccer ball head illusion). [EDIT] I'd also like to add Space Battle V2 is out now Now supports teams(2 teams of up to 4 players each), up to 8 person FFA, 1 new ship design(now 4 saucers, 4 winged ships- 2 of each per team) and gameplay fixes.