Funny "thump" sounds sometimes at night, what could be the cause?
If your basement has a honey bucket sump or water sump pump, what you might be hearing is it shutting off. I have both in my basement. The regular water sump (which gets water from the drain tile and from A/C) runs quite regularly, especially during the rainy season. It is rather noticeable when it runs and shuts off ... it's sounds off when shutting off, but not too badly. The honey bucket sump (sewer evac for basement bathroom and grey water) kicks on every now and again. When it shuts off, there is a large noticeable thump from it. I don't know how to fix the issue, but it does do it. I hardly pay any attention to it because it is a known sound in the house which usually doesn't happen very often.