It's a couple of appenders I've found useful - basically a model for decorating other appenders (by extending DecoratingAppender) together with a couple of examples, one that cleanses Groovy stack traces so you don't get all the useless frames and one that makes any appender asynchronous with a configurable number of threads used.  There's an example logback.xml showing how to use them:

At some point I might try and release this as a library via Maven, but in the meantime if anyone finds them useful go ahead, and Ceki if you fancy them for Logback.  Equally if anyone has any pointers (e.g. have I reinvented the wheel?) do let me know.

Rob