Obviously these kids are choosing your house for a reason, instead of other houses. Maybe you react the most "funny" to them when you spot and try to catch them. Maybe your house is an easy target for some reason (no 10 cent security sticker in your window, etc). It's possible you change these factors to convince them to leave you alone, although by now it might be their tradition to attack YOUR house.
If they attack on a regular schedule you might be able to anticipate them, pretend you're not home, watch out for them, call the police if you spot them trespassing. If you explain what's been happening you might be able to make arrangements for plainclothes officers in an unmarked car to show up instead of an obvious one that will just cause them to run.
Some limited video surveillance would be very useful in getting these guys arrested. Even without pressing charges this will likely convince them to go bug someone else.
And of course the very presence of a camera might encourage them to try an easier target.
But confer with a lawyer before doing anything in this regard. In some places it's illegal to make audio recordings of people without their awareness and permission, even if they're on your property. Some dude is getting sued by law enforcement because he kept a video camera trained on his porch and he tried to present evidence of a police officer harassing him. Not a pretty turnaround.
Or you could just rig jack-in-the-boxes in some of your trash cans...
But seriously... they're treating this like a game, and it sounds like you're trying to get the police to fight for you, and not really doing much yourself. You gotta stop skipping your turn and make your move.
If you're inventive enough you can even make it fun... but as I said before... keep it legal, or else you'll get in more trouble than those kids have been giving you.
Another strategy that occurred to me is probably going to be the most effective. If you can figure out who they are, and contact their parents, assuming their parents aren't from the "the government should babysit our kids for us!" group, it should be fairly easy to put a stop to it from there. The real problem might be identifying them once you have pictures (you can, as I suggested before, pretend you're not home and hide with a camera, though the legality of this would need to be verified). The police might be able to help in this respect, as it's possible they know those kids all-too-well. Otherwise you can always yell to the kids next time you see them that you're going to post their pictures all over the city/town with offending captions. Of course, you don't need to actually DO this (and it IS likely illegal anyways).
Those are just some of my ideas, feel free to be inventive, but again, I'm no lawyer, so tread carefully.
On second thought, probably the best thing to do without worrying about legal hot water is to ask the police for advice on what you should do.
That's what I do...
