A recent concept (Me give attribution? On the web?? You must be joking!!!) in waste of www time: Go to Google, and type in search terms which yield precisely one result.
Sure, if you type in ``"Mary Poppins" "tensor calculus" foo bar'', you'll get nothing. That's not a challenge! But try getting exactly one...
The next step after finding a successful googlewhack is to publish it on your blog, your friends' blogs, Everything2, SlashDot, Kuro5hin, and everywhere else. This has the unfortunate side-effect of destroying the googlewhack, of course. But such is the self referential online life.
Googlewhacks are parametrized by the number of terms or words that they contain. Of course, stepwise refinement towards a whack, as evidenced by words from the same domain, does not count. A 1-term googlewhack is relatively easy, as are 5-termers. The grail here is the 2-word googlewhack; for this writeup I came up with my first (current for January 31, 2002):
Zerotime recommends "monitron pants".