Something I did once - it caused me a 'bit' of trouble, but I felt it was worth it.....
I live on a very small estate (about 40 house) at the side of a 'nice' area (V big expensive houses). My estate is a mixture of civilian and military private tenants and there has never been any trouble. All of a sudden we started having a lot of problems with teenagers, not from the estate, scratching cars, destroying fences, making loads of noise etc etc. They were always really abusive when challenged and people who had challenged them would find their cars and houses damaged shortly after.
Called the police a ton of times and when they eventually (usually a couple of hours) turned up the culprits would be gone and nothing would be done about it.
Well finaly I had an idea. One night when these gits were being really bad (had set a fire in the kids park and were dancing round it) I phoned the police (same number as always) put on a dippy voice and said I was 14 and had just been punched by an adult on the estate.
Well, the police got to the estate in about 15 mins and caught the gits destroying a car (they'd smashed a back window and put a burning bench plank from the park into the car.
They took all the kids (there were about 8 of them) away and a few months later there was a court case and they got ASBOs n stuff (and you know every single one of them was from the 'nice' area, that look down on our estate)
I did get into trouble for doing it - my phone number of course - but essentially I got a smack on the wrist and told not to do it again......... The cop that came round actually said he applauded my initiative!