According to the Jargon File a "killer app" is an "application that actually makes a sustaining market for a promising but under-utilized technology." A "killer example" provides clear and compelling motivation for a design pattern or design principles. An example is "killer" if it compels someone to spontaneously "buy-in" to that design pattern or technique.
"Killer examples" are important pedagogically because they get students on-board and excited about design in general and design patterns in particular. They are useful to convince peers or employees, not familiar with object-oriented design, that design patterns are central to good object-oriented practices and that they are not an esoteric topic that is best left to expert.
The workshop's goal is to bring together educators and developers who have "killer examples" to share. Pre-workshop activities encourage interaction and refinement of examples prior to the workshop.