Not me, but then again I'm not an idiot!
j/k
I couldn't log into my yahoo account for 2 days to make line up changes. I'm glad I had set them for Mon and Tues. Yesterday I couldn't login to my yahoo account again until I rebooted my PC. At first I thought is was yahoo but when I couldn't login to my MSN or Earthlink accounts I figured the problem was on my end. One reboot and all was ok.
You may also try clearing you history and cookies, it will screw some other things up but if all else fails give it a try.