Well - I do know the obvoius answer is to replace the damned thing, But I'm trying to figure out what happened. I have to climb up and clean out the glass. This was a stationary skylight that decided to blow today when I wasn't home. The good thing is that only one of the glass panels broke (interior), and the exterior one seems to be holding, so no immediate need to head to the roof and cover it up for rain. By the chunks of glass - I'm guessing it's tempered, so a little bit easier to clean up. My best guess right now is that they are probably about 20-25 years old (I've been in the house for about 14 years). They have always been "foggy" in the summer, so I know the seals in between the glass were going, but there's never been any leaks. The windows are at the south side of the house. This morning it was cool (maybe 50*), so I closed up all of the windows early this AM. We had some pretty bright sun and a quick warming this afternoon, followed by another small rain storm. So what I'm thinking is that it was more of a temperature difference/pressure change which could have caused the break. I really doubt there was any stress from the framing which might have "squeezed" the window to cause it to break.