...One user suddenly had trouble which he traced to the neighbors CFL post lamp...
Actually, it was a wall-mounted light on his front porch ;-)
But I wouldn't be surprised if a neighbors holiday lights (which are generally off during the daytime, and only on at night) might be causing the issue.
Try to test during the day, and then again as each neighbor turns on their lights.
If you are friendly with the neighbors, you could wait until your lights stop working, and then ask each neighbor (one at a time) to turn their lights off for a few minutes, so you can test.
If you find the neighbor whose lights are causing the problem, you can then ask if they would mid turning off each section of lights on at a time, so you can test which one might be causing the interference. You might want to offer to buy filters for them to plug their lights into.