Some RFCs are not as serious as others. Beside the early stages, where poems made it into the internet standards, almost every year there is one (or more) RFCs for April fool’s day. Look out for the publication on "April 1" in the RFC index, all normal RFCs do not carry the day of publication but only the month. And some RFCs are provide guidance and principles beyond the technical standards. Here is a list of them.
RFC 527 ARPAWOCKY, by R. Merryman, May 1973 - [ html | txt ]
RFC 968 Twas the night before start-up, by V.G. Cerf, December 1985 - [ html | txt ]
RFC 1121 Act one - the poems, by J. Postel, L. Kleinrock, V.G. Cerf, B. Boehm, September 1989 - [ html | txt ]
RFC 1300 Remembrances of Things Past, by S. Greenfield, February 1992 - [ html | txt ]
RFC 1178 Choosing a name for your computer, by D. Libes, August 1990 - [ html | txt ]
RFC 1925 The Twelve Networking Truths, by R. Callon, April 1 1996 (also in the april fool’s day list) - [ html | txt ]
RFC 3254 Definitions for talking about directories, by H. Alvestrand, April 2002 - [ html | txt ]
RFC 1118 The Hitchhikers Guide to the Internet, by E. Krol, 1989 - [ html | txt ]
RFC 1855 Netiquette Guidelines, by S. Hambridge, 1995 - [ html | txt ]
RFC 2901 Guide to Administrative Procedures of the Internet Infrastructure, by Z. Wenzel, J. Klensin, R. Bush, S. Huter, 2002 - [ html | txt ]
RFC 3184 IETF Guidelines for Conduct, by S. Harris, 2001 - [ html | txt ]
RFC 3227 Guidelines for Evidence Collection and Archiving, by D. Brezinski, T. Killalea, 2002 - [ html | txt ]
RFC 3283 Guide to Internet Calendaring, by B. Mahoney, G. Babics, A. Taler, 2002 - [ html | txt ]
RFC 3439 Some Internet Architectural Guidelines and Philosophy, by D. Meyer, 2002 - [ html | txt ]
RFC 3470 Guidelines for the Use of Extensible Markup Language (XML) within IETF Protocols, by S. Hollenbeck, M. Rose, L. Masinter, 2003 - [ html | txt ]
RFC 4181 Guidelines for Authors and Reviewers of MIB Documents, by C. Heard, Ed., 2005 - [ html | txt ]
RFC 4677 The Tao of IETF: A Novice’s Guide to the Internet Engineering Task Force, by P. Hoffman, S. Harris, 2006 - [ html | txt ]
RFC 5411 A Hitchhiker’s Guide to the Session Initiation Protocol (SIP), by J. Rosenberg, 2009 - [ html | txt ]
RFC 5564 Linguistic Guidelines for the Use of the Arabic Language in Internet Domains, by A. El-Sherbiny, M. Farah, I. Oueichek, A. Al-Zoman, 2010 - [ html | txt ]
RFC 5706 Guidelines for Considering Operations and Management of New Protocols and Protocol Extensions, by D. Harrington, 2009 - [ html | txt ]