Easter eggs can be fun, but you got to be careful too! I know of a group that put a "PC Load Letter" error on a $100k machine as a joke (Office Space reference), all in good fun. Well years later a unit completely broke, kept saying "PC Load Letter", and caused a big problem for the customer. Somehow an executive caught wind of the whole situation and was not too pleased...<p>So maybe the moral of the story is put Easter Eggs where a user can find them to have fun, not as an error message!
I prefer James Thomson's presentation on the history of easter eggs: <a href="https://www.youtube.com/watch?v=fAaqSr-yShc" rel="nofollow">https://www.youtube.com/watch?v=fAaqSr-yShc</a>