Quixote-1.0 is a library that eases access to the quest log, and provides (far, far) more helpful events than the default Blizzard ones. It also communicates quest status between Quixote users in a party.
It began life as part of QuestsFu, but was split out so that others could use it. Also, selfishly, so that its communication features would spread as far and wide as possible.
Quixote is used in:
...and maybe others.Quixote's API can be found on wowace.com, autogenerated from comments in the source.
Quixote's SVN trunk is here: http://svn.wowace.com/wowace/trunk/Quixote/