Reminds me of when I had to write a front-end for a web search feed. It was easy to test the standard case (millions of results, of which the first 1000 can be paged). But what about the case when there is only one page of results? The solution seemed to be, rather than finding a topic with only a few results, to keep appending common words until the # of results shrunk enough. For example, from Google:

  "antelope" has 14,100,000 results
  "antelope walrus" has 118,000 results
  "antelope walrus biscotti" has 8,100 results
  "antelope walrus biscotti eisenhower" has 1,690 results
  "antelope walrus biscotti eisenhower lambchop" has 8 results!

Bonus if you can find a word combo which produces a single page of interesting sites, not word spam. Of course now that this comment is on the web, make that 9 results for "antelope walrus biscotti eisenhower lambchop".