1. It's an attempt to engage the class. This is an opportunity for them to be creative, funny, and maybe, just maybe, smart (they almost never have me search for a topic related to their assignment or class...)
2. I get to show them what happens when they search using too broad of terms.
For example, yesterday I taught 4 classes. In 2 of them I asked the class to tell me what to search for during my demonstration of LexisNexis' Search the News. In the first class a kid said "dogs" then I showed them what happens when you just type in dogs. I asked for a narrower search. His answer? "Dog bones."
2nd class: A kid has me search for "partying." I ask him to be more specific. What ABOUT partying does he want to know about? "BEER!" "GAMES!" At least with this one I got to show them "beer and games not liquor."
So, sometimes these attempts to make class "exciting" DO work out. Other times it just becomes awkward for everyone involved.