In his monthly neologism challenges before he retired in 2004, Washington Post columnist Bob Levey famously asked his readers to send in new words made by taking existing words and adding, substracting, or changing one letter to yield a new definition.
A list of some of the funniest wordplays has since been circulating around the Net for years. For those of you who haven't seen in before, Miss Cellania has quite a few:
1. Cashtration (n.): The act of buying a house, which renders the subject financially impotent for an indefinite period.
2. Ignoranus: A person who’s both stupid and an asshole.
3. Intaxication: Euphoria at getting a tax refund, which lasts until you realize it was your money to start with. [...]
5. Bozone (n.): The substance surrounding stupid people that stops bright ideas from penetrating. The bozone layer, unfortunately, shows little sign of breaking down in the near future. [...]
7. Giraffiti: Vandalism spray-painted very, very high.
More Bob Levey's Neologism Competition at Fun With Words: Link