RFC 6921 has been published today:
We are approaching the time when we will be able to communicate faster than the speed of light. It is well known that as we approach the speed of light, time slows down. Logically, it is reasonable to assume that as we go faster than the speed of light, time will reverse. The major consequence of this for Internet protocols is that packets will arrive before they are sent. This will have a major impact on the way we design Internet protocols. This paper outlines some of the issues and suggests some directions for additional analysis of these issues.
What makes some April Fools RFCs so good is that they are scientifically accurate. Currently internet protocols do need to be able to deal with packets arriving out of order (it can happen for many reasons). However the situation where replies are sent before requests has not received enough study. This RFC has some excellent analysis of just that.
A book of all the funny RFCs though 2006 can be purchased at www.rfchumor.com. It is the perfect gift for the geek that has everything. It makes a great book to leave around the office or home for casual perusing.