Wikislip
The condition which sets in when you read a wikipedia article and are interested by multiple links in - so you open those and are interested by multiple links inside those, as well - this condition is usually ended when you think to look at a clock and notice that you have just lost hours of your life looking up information not even slightly related to your original subject.
So I was researching Cherenkov Radiation - one wikislip later, it's 0300 and I'm reading up on Kevin Bacon.