My idea for an AVP story was the Predators drop Alien eggs in pods onto a colonized planet waiting for humans to find them and breed the Aliens. With the disappearances of the colonists in the jungle outside the colony, they bring in the Marines to investigate. But the Marines get into a jurisdiction issue with Weyland-Yutani who have come to take over the operation (but really they're after the Predator technology). The Predators arrive to hunt the Aliens, little do they know, that an Alien Queen slipped through the cracks (which I got the idea from the first AVP comic book), so the Alien population is gonna get out of hand. So the Marines have to help the colonists escape, but to make things worse, one of the Wey-Yu officers stole a Predator wrist-computer from a recently killed Predator, so now the Predators are going after them to get it back.
Well, that's my idea. I wrote a screenplay, even wrote two sequels, and two different AVP stories, while trying to write more, if I ever get time.