a few times in my teens. It wasn't pleasant. None since.
I did, however, have a really freaky experience not too long ago. On 2/22/11 at 2:22 a.m. I woke up with a start, stick-straight up out of bed in a cold sweat. I'd love to know what that was all about.
When a true genius appears in the world, you may know him by this sign: that the dunces are all in confederacy against him. ~J. Swift