A (perl) project I'm working on requires many fast DNS responses, so I'm looking at Danga::DNS. This is developed by Matt Sergeant (who works for MessageLabs) as part of Qpsmtpd. However, contrary to usual I don't want it to cache my results, so I modified the code to provide a cache_enable option, which defaults to true. A very minor update (less than 10 lines over 2 modules) but I feel somewhat proud of my achievement :)
The update isn't in the codebase at time of writing as Matt has many things on. But it will be, soon :)
How is this related to LiveJournal I hear you cry? Well, Danga is the open-source development branch of the team that originally developed LJ. :)