If you don't mind being frisked by your local friendly constable then try the following:
1. Purchase some squibs, place outside house in direct line with one of your windows. Hidden obviously
2. Purchase laser pointer
3. Point laser pointer at ground around kids (from behind curtains) and set off squibs.... shouting, bawling, screaming blue murder as an accompaniment is also beneficial.
4. Watch ruckus makers disperse like the wind.
5. Watch cop car pull up (but not before feeling of much satisfaction...)
Same effect can be had with pistol & blanks but will get you in even more trouble and earn you much condemnation from society.
In fact same effect can be had from potato gun loaded with turnip...heh
Of course you could always just resort to leaving a couple of stink bombs outside. Just make sure you own a nice handy gas mask.
The surest sign there is intellegent life in the Universe is that they havn't come to visit us yet - Calvin & Hobbes