RFC 2324 - Hyper Text Coffee Pot Control Protocol (HTCPCP/1.0), a protocol for controlling, monitoring, and diagnosing coffee pots.
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.
This is almost as bad as IP over avian carriers