Is there any way to find out why 3 squad cars were at my neighbor's house last night?

A lot of times there's a crime beat in the local paper that lists the calls and what they were for. Sometimes this is also online. Sometimes local police departments have a crime beat or like ours has a map. They list the types of crimes and then show on the map where they occurred. So try going to your police department's and local paper's websites first. Good luck. I would ask around to the neighbors but I know what it's like not to know anyone and I'm shy. You don't get to know people until you get to know them, you know. :)

State laws vary, but I know in California department policies are governed by the California Public Records Act (Government Code Section 6250-6260).

This is supposed to allow for access to public information, however there are limitations. Police reports cannot be viewed in electronic form and if it is an ongoing investigation that may go to a criminal trial, they will most likely not be released to the public. Often, you must be listed as a victim or be an attorney representing someone who is a victim, to receive a copy of a report. Additionally, police reports can take anywhere from 3-7 days to prepare, so one would not be available in any case if the incident occured last night.

If it is an "incident report/event report" you may be able to view basic information on the police department's website, but they won't have much information. However, if 3+ police officers were there for an hour and a half, it is likely a criminal matter.

Oh

You're looking for a lazy way to find out.

I had a way, considering police reports are public records, but that'd involve you getting out of your chair.