Cap'n, you said the operative word..."stumble".
Some folks have discovered the joys of the
StumbleUpon plugin for the Mozilla
Firefox web browser.
Basically, it allows you to channel surf the web, hitting more or less random web pages that other people have liked enough to add it to the database. You preselect categories when you register (free, no spam) and create an account. This likely came from the humor category. Sometimes you find some interesting things there. and sometimes I also Stumble across something dumb like a Google search page.
The worst side effects are loss of sleep and a huge bookmark file.
Brian