1: In College roughly 20 years ago, by accident (dial "9" to get an outside line, "1" for long distance, but the phone malfunctioned and dialed "1" twice). Campus police showed up a few minute later to complain about the crappy phones the university supplied the dorm rooms with.
2: About six years ago: My wife was very ill. No police but an ambulance and fire truck.
3: About five years ago: Fistfight in the driveway of the house a few doors down from mine. One left before the police arrived. The other (the father of one of my son's friends) soon after moved to "Maryland", which has since become a euphemism in our house for "prison".
4: About five years ago: Witness some youngish adult looking people throw a rock through the window of a church (not my religion, but I called anyway). I was too far away to see anything useful, but the Bishop was happy to be informed so he could tape it over before it got any weather damage.
5: About four years ago; to report a wildfire. ("This is 911, are you calling about the fire?")
6: About three years ago: Found a pair of rifles laying in the middle of the road. Before the sheriff's deputy could arrive, the owners returned, having already gotten home and noticed that the rifle case was no longer on the ATV trailer. They could not decide whether to act sheepish about losing the rifles, or angry at me for calling the police, who they did not wait for.
7: Two years ago: wife was very ill again. Norovirus, nasty stuff.
8: A few months ago: People riding motorcycles on the bike paths and grass of the local park, tearing up the grass with spins and uphill runs. I felt kind of bad about that one, like I am some sort of old curmudgeon, but I don't like to see my neighborhood park torn up. The riders left soon after, and I never did see the police show up (although they had been in the park the previous day for the same issue).
ETA: I just remembered one from about 25 years ago. My girlfriend heard something outside and my dog went crazy. She thought she was being stalked by her ex. She might have been, I don't know. Police came, looked around, didn't find anything.