I have run this a couple of times at NOVAG events, and it seems to be a pretty fun, and close-fought battle to boot.

Situation:

You have just completed the first Gargant for the soon-to-be-declared Waaagh-Ork that will be started here on your home planet of Munkar VI. The Celebration went on all night long, and finally after all the Squig-juice and grog was drunken by your mob of Waagh-happy orks and gretchin, the Boyz tottered off to sleep anywhere there was a clear spot.

At the start of each turn, roll a d10 for each mob. If less than their Initiative, they "wake up" and can move, fire, etc. that turn. If firing of weapons has occurred, then mobs need only roll less than their Leadership to awaken.

Marines are the first player. Orks are deployed first, on ground level, within 12" of the Gargant. The only exception is that the Mekaniak and his Gretchin may start inside the Gargant. This scenario last 10 turns. Victory is determined at the end of the Ork turn 10.

Mission:

Defend the Gargant from the blasted 'Oomies! Kill 'em all!

Forces: You have two 10-ork mobs of Ork Boys and three 10-gretchin mobs. Additionally, you have a Warboss and a Mechaniak with 3 Gretchin assistants each.

Equipment:

Each ork has a bolter and a hand weapon. Sorry! No grenades! You used them up during last night's party! The Gargant, while complete, has no fuel for it's bunkers and no ammunition for it's guns, so it can't move or shoot.

Victory Conditions:

Undamaged Gargant & all Marines dead = Total Ork Victory
Undamaged Gargant & Some Marines alive/escape = Substantive Ork Victory
Undamaged Gargant & 1/2 Marine force alive/escape = Marginal Ork Victory
Destroyed Gargant & all Marines dead = Draw
Destroyed Gargant & at least ONE Marine is alive/escapes = Total Marine Victory

Spacemarine Player

Situation:

Your squad has been deployed secretly onto the planet Mukar VI, which is a former Imperial world, now held by the Orks. The Orks have been building a Gargant, which only now is nearing completion. It is intended to be the start of an attack aimed at the heart of the Imperium. Marines are the first player. The entire squad must enter from any one of the 4 sides, a within 8" of the center of the side. This scenario last 10 turns. Victory is determined at the end of the Ork turn 10.

Mission:

You must destroy the Gargant at all costs! Kill as many Orks as possible and do your best to escape back to the drop zone (a pre-determined board edge).