How to deal with bratty children that aren't yours?

You sound like a smart kid for your age...you write well (which actually says a lot). I'm sure you can figure this out. To help you though, I would probably first tell your grandmother why you have no interest in playing with them. If you continue to have to, then it's time for you to be boring. Do not let them play your video games anymore. Say, "I don't want to play with you today, because ________; but if you insist on playing, then THIS is what we're going to do. The first time you act like a spoiled little snot, I'm going inside and you can go home." If you have a chance to take them home, explain to whoever their so-called authority figure is that you tried to play with them, but _________(<~~here's what happened). Good luck, whatever you do.