http://tools.ietf.org/html/rfc2324#section-2.3.2
2.3.2 - 418 I'm a teapot
Any attempt to brew coffee with a teapot should result in the error code "418 I'm a teapot". The resulting entity body MAY be short and stout.
Geek Humor, a complete and well defined schema submission to the w3c for HTCPCP/1.0. Brilliant!
HTCPCP of course is the well known acronym for “Hyper Text Coffee Pot Control Protocol (HTCPCP/1.0)”.