There are any number of reasons why those wasps are ending up in your children's bedroom. But what we need to ascertain first is what kind of wasp we're dealing with. The way you characterize these attacks seems to imply that these wasps are either particularly aggressive (yellow jackets) or they're more territorial (hornets and paper wasps). It may be that you'll have to find one of these wasps, kill it, take a picture of it and post a link to that picture here. Or find us a good example of the kind of wasp you're dealing with on Google Images and link to the result. From there, we might be able to figure out what kind of wasps you're dealing with and from identifying them, we can go ahead and formulate a remedy for your wasp problem based on the patterns behavior of those particular wasps.
Sound good? If you need more info about getting rid of wasps, I would check out our article here: How to Get Rid of Wasps, and go through the various types covered, and try to figure out which wasps you're dealing with. The advice offered there is probably the best advice I can give.