One of the simpler of the E2 nodelets - Random Nodes simply grabs 13 random node titles from the database and
offers up their links - for good or for ill. Usually one or two are just nodeshells and one or two others are Websters 1913 definitions. It will also dredge to the surface many writeups from many years ago - some of which you would have never bumped into otherwise.
This nodelet refreshes every 10 minutes and each user who has it on will see the same 13 node titles. You can turn it on or off in your user settings.
Lord Brawl notes: THe XML ticker is serviced by a different function. It does not serve up the same set of links as the nodelet (except by mind-boggling coincidence).