Your current filters are…
In a world where MetaObject Protocol hacks like methodMissing provide quick ways to create DSLs, Groovy's BuilderSupport class is a less known but a very powerful tool that makes this process easier and provides for some structure around such implementations. While prone to tree structures, a little tuning can create terse yet flexible vocabularies.
Another approach to DSL's in Groovy involves a combination of Categories and Groovy's pseudo operator overloading. While this approach may well provide much more fluent DSLs, implementations usually end up fragmented.
The session could (very well should) demonstrate several examples of such DSLs of varying complexity; but not before having demonstrated the plethora of builders already available in the Groovy ecosystem.
4th September 2010