Technically, a "Googlebomb" is a kind of link prank where some webmasters try to put someone else's
website at very high rank for a meaningless query.

One of the famous Googlebomb was for the phrase "misrable failure,".

Many webmasters link this term from their website for US president George bush and direct the link containing anchor text "misrable failure" towards White house website.

So whenever someone type misrable failure in Google search engine the US white house website comes at page one rank one.

However now Google has came up with an algorithm that minimizes the impact of many Googlebombing.