Kadath

Well, that's definitely unnerving. As comfort I would offer the fact that once you start to get freaked out, the more you'll look for things that freak you out, and the more effect each thing will have on you.
I'll go through one by one, not to debunk your ideas or mock you in any way, but to try to provide some outside clarity. Your daughter's toys were the first thing. Each could be a simple electrical short that triggered the sound, though both happening sequentially is pretty odd. As for the pipe and cigarette smoke, memory and smell are very closely linked. Perhaps something triggered that memory in your brain. Though, again, it's odd for a memory to be concentrated in one area.
The spot of light should be investigated. See if you can determine its source, and thus put your mind at ease about it. How large of a circle? Have you tried tracing it back to the blind?
Hot and cold spots are not uncommon in a house. Perhaps the heat from the computer warmed the area noticeably.
The situation in your office is probably one that has happened before, but you never noticed it. Given that you are so alarmed by previous events, you likely accorded it more importance than it actually possesses.
I admit that all of these are a lot of ifs, and Occam's Razor would seem to suggest the answer you feel makes the most sense is correct, but see if you can eliminate some or all of these, and then consider if the freakiness diminishes. Also, look at everything odd that happens with a critical eye, and especially look at your reaction to it. Would you have noticed it before?
Good luck, man. Keep the info coming.

__________________
it's quiet in here