BGP ASN Allocations
BGP is Border Gateway Protocol. An ASN is an Autonomous System Number. BGP uses ASNs as identifiers to keep track of autonomous systems.
An unsuccessful experiment with BGP on the PersonalTelcoVPN once used the ASN 65503.
This ASN was registered on a FreeNetworks wiki page which provided a registry to help coordination of ASNs used by community networks. Sadly, that wiki seems to have completely disappeared.
ASNs in the range of 64512 through 65535 are reserved for private use according to RFC 1930.