Dress up in your camo get some of your buddies to do the same. Get some walkie talkies. Arm yourself with eggs and paintball guns. Lay and wait. When the little suckers come a calling, return fire, with above said ammo. THEN, and this is the part that will teach them the lesson, follow them undetectedand employ guerrilla warfare as they try to attack a neighboring house or developement. Keep up the fight untill they give and then ask them why they don't want to play that game anymore.

Short Story, I have a riverlot, kids USED TO sneak in and steal beer and head to the cornfield to drink it and then return for more. My buddies and I miked up and messed with them all night to the point that they are unsure of our sanity and haven't touched a beer of ours for two years.

PS. Its also a hell of a good time if you are up for it. Good luck and don't introduce real guns until necessary.