Presented straight from the shower, unplaytested and unrefined, it's Mechaton: Junkyard Wars (or Mechaton: Scrapyard Challenge for those of you across the Atlantic)

What you need:
a circular table
a big pile of LEGO parts, some suitable for making Mechatons
some friends

Setup

Scatter cover around the edges of the table like you would for the Short Game.

Put the big pile of LEGO in the center.

Decide how long the Building Phase will last.  I have no advice on this (see note about playtesting) but if you have lots of parts or your players aren't as familir with LEGO, I would make it longer.

Play

1. Building Phase.  Everyone has the agreed-upon amount of time to put together a mech to run the course. Should you be able to have multiple mechs? I'm not sure - that would make it to easy to have a single mech specialized for each challenge. So I'm thinking no.

2. Course Setup. Pick a direction to be the starting point and call that 12 o'clock.  Place each other challenge station randomly based on a d12 roll.  What should you do if two stations come up at the same place?  I'm not sure of that either - you could reroll but it could be interesting to combine the challenges.

The chellenge stations are:

Green: this is just an ordinary station. End your turn as the only mech in HTH range to put your flag on it.  (Your flag will stay on it even when an opponent adds his - so if everyone completes the Green challenge it will have everyone's flags on it.)

Blue: this station has machine guns that will fire at the closest mechaton in drect fire range.  It gets an initiative die and two red dice at direct fire range, but nothing else.  I'm not sure of you can blow it up or not.  Other than that it's a regular station: end your go in HTH range to put your flag on it.

Red: this station has a target for each competitor. Each target gets a blue die.  To complete it you need to destroy your target (hit it and take away its blue die).

Yellow: there needs to be a spotting challenge but I'm not sure what it is.

3. The Challenge Complete as many stations as possible before the doomsday clock runs out.  You can do them in any order, but your opponent can also try to destroy you.  Maybe you can only do that after a certain amount of time has passed on the doomsday clock? Or maybe mecha who haen't taken a station are immune unless they attack?  I'm not sure what would work best.

4. Scoring. Just like Mechaton - number of mecha (which probably should be 1) plus number of stations completed times points per.

I'm stealing your race idea. A large number of stations, everyone starts roughly at the same place and whoever grabs a a station first keeps it. Stations that fire are the nearest mech is a nice twist.
I'll try that next monday game.

Uriel wrote:
I'm stealing your race idea.

Or, you know, how it went, since I didn't read the date of the last message or anything.