At least you don't have an ominous damp on the ceiling in your bedroom where it meets the exposed brick, which also has a bit of ominous damp. I'm steeling myself to climb up on the roof to see what's what. I'm hoping it's just a blocked drain (which will cause water to infiltrate the tightest roof) and not, you know, a roof problem.

Do you have a dehumidifier? They're not to expensive and do a really good job of drying things out after you get rid of the standing water.