CHECK YOUR SMOKE DETECTORS!
This is our laundry light. The laundry is right next to the children's rooms and is left on sometimes if they're fussing about the dark.
On Thursday night the husband & I could smell something burning - only faintly, and not enough for the smoke detectors to pick up, but enough to alarm us. Then we spotted the old plastic lampshade on the laundry floor, and looked up to see a bare globe covered in something drippy & heating up alarmingly.
From what we can figure out, the plastic of the lampshade became old and brittle (age, the heat from an incandescent light bulb & the humidity of the laundry) and eventually snapped off the fitting, so the plastic itself was resting on the hot globe, where it proceeded to melt.
We were lucky and found it before it caught fire, and we do have smoke detectors, but it could have been nasty.
Go test your smoke detectors now - and if you don't have them, get them.