The act of manipulating Google search engine results by having hundreds of sites link to a specific site using deceiving keywords.
Google "miserable failure" and you'll get the bio of George W. Bush...he's a victim of a googlebomb.
A Googlebomb is an effort to make as many links as possible to a certain website from various other websites to increase the pagerank of that certain website, increasing its rank on search results for a certain search. The aim is to make your website appear as the first result for a specific search term.
The first search for "Finding Chuck Norris" is a page that looks like a google search result telling you "Google won't search for Chuck Norris because it knows you don't find Chuck Norris, he finds you." This page was googlebombed to the first rank under "Finding Chuck Norris".