A miniature painting and modeling contest run at Games Workshop's Games Day conventions. Entries are sorted along several criteria, including age of creator, type of model (single miniature, monster, vehicle, diorama, duel, squad/regiment, large-scale model), and franchise (Warhammer 40,000, Warhammer Fantasy Battle, and The Lord of the Rings), with Bronze, Silver, and Golden Demons going to each category. Forge World also picks a miniature they like as their Best In Show.
Winning entries are always beautiful. It's almost enough to make you forget how much the miniatures cost...
The competition is named for its prize, a golden statue of a Demon posed in a manner reminiscent of the Oscar award. The overall winner also gains the Slayer Sword, and sometimes some other prize (a lead Thunderhawk Gunship was given to one UK winner, for example). It is the one time Games Workshop does not spell it "Daemon." Yes, we'll wait while you check.
How To Win
If entering the vehicle category, enter a Dreadnought. Anything other than a Dreadnought seems to have an automatic disadvantage with the judges.
Unlike regular modelling contests, the judges will not be trained sadists armed with digital calipers and flashlights to check engine bays to see if you've put a fully detailed engine where nobody will ever see it. So if you can't see it, don't worry about it.
Sneak as many parts by other manufacturers in as possible. This works less well after Kevan Downey in the UK entered what was obviously a converted Tamiya Dragon Wagon model and White Dwarf gave it the full textual handjob before realising the "tiny chains" they'd praised him for adding were part of the stock kit.
"Judges will be looking for well-painted models that adhere to the imagery and ethos of the worlds represented in the fictional worlds of Warhammer and Warhammer 40,000." This means you can't troll them and try to win with your squad of Female Space Marines or Squats -- though now that Squats are canon in 6th Edition...
How to not win
There are people out there who will paint your models to professional standards for cash. There is also a rule saying that the person who painted the model must be present or the prize is forfeit. Several people have been caught out in the past trying to pass off professionally painted models as their own work; strangely, the painters tend to not be too pleased seeing their work in the awards list under someone else's name, and they will do their level best to get you busted if you try it.
Seriously, there are so many amazingly painted and modified miniatures and dioramas out there, so you'd better Google that shit. I don't have the energy to add a bunch of pictures here, because there are so damn many, mainly because of the many categories and also because the competition has been running for a while. AND mostly important because it would be unfair to many winners that some are shown here and some not.