I've never been a huge fan of Easter Eggs. From a risk management and QA point of view: there are a lot of things that can go wrong in a software project, why deliberately add something else not asked for, even if there was only a 1% probability that it would break? It just seems that the downside risk massively exceeds any potential upside. If something actually fails because of it and you have to write the postmortem, what are you going to say?