We live in a 100 year old brick 2 story with a walk up attic. All 4 bedrooms on the 2nd floor have ceiling light fixtures. Since we moved in about 7 years ago we have noticed a few times that the ceiling lights in the bedrooms will quit working. No breakers tripped, outlets still work in the rooms. After a while they start working again. I didn't give it too much thought until about a week ago when it started happening about every day - usually in the afternoon. Any ideas on what could be causing the problem? Thanks.