Oh sucks to be you. I HATE other peoples kids. HAHAHAHA! No really sorry to hear about your trashy neighbor. Maybe you can sell the kids off to china for sweat shop labor.
I lived in a duplex when I was in my junior year of college. The people next door had three kids who were always screaming and hollering when my roommates and I were trying to sleep or study or just hang out without hearing crying and shrieking all the time.
My boyfriend rigged up a wonderful device that was basically an electric grid. We placed it under the window where the tots habitually congregated and disguised it with some debris. As soon as the kids started making a racket we'd complete the circuit that electrified the grid and the little pricks would get zapped. They never figured out what it was. The parents thought bees were stinging them and eventually, like good little rats in a Skinner box, the brats started playing away from our side of the house.
I wish we had made a video of them getting zapped. The best time was when the little bastards were wet from squirting each other (and our beach towels and our grill) with super soakers. Wet little bastards plus a jolt of electricity equals big fun for harassed college students.