Personally, I would just ignore and drive carefully.

People don't play right at the entrance to my neighborhood-- but that's probably mostly because 1. there are no houses right off the entrance-- you have to drive a bit before you get to homes or other roads, 2. our neighborhood entrances (there are 3) are off of a six lane road that is currently under construction being widened to an eight lane road, and 3. there 1200+ homes in our neighborhood so that's a lot of traffic.

However, with that many homes in our neighborhood, our neighborhood streets see quite a bit of traffic. I actually kind of like it when I see a good sized group of kids out playing in the street (as long as they're not being rude and refusing to move out of the way for cars). I can't imagine any of my neighbors complaining about it. I know my HOA wouldn't do anything about it. I'm even fairly confident the police wouldn't do anything about it if they were called out (except maybe join in and play with them for a few minutes and then remind them to keep any eye out for cars). Seeing kids out playing just reminds me that we live in a family neighborhood.

I also saw where you asked another mom why they wouldn't just choose to play in someone's yard. In our suburban neighborhood, even the largest lawn doesn't leave much room for tossing a football or frisbee. Playing in the street gives the kids more room to spread out and really enjoy themselves.