Yes, I've called the police on numerous occasions. One was to report a pedestrian with a handgun(in reality it was a fake gun. the police said the guy was lucky they didn't shoot him as the gun looked very real)
Other occasions I've called the police on neighbors that were fighting and yelling beyond an acceptable level.
I've been in my neighborhood for 5 years now. The first couple of years I had to call the police many times. Now, I can't even recall the last time I dialed 911. It's quite peaceful now, but I won't hesitate to get involved and call the police when necessary.