OpenTTD is an open source clone of the Microprose game “Transport Tycoon Deluxe”, a popular game originally written by Chris Sawyer.
It attempts to mimic the original game as closely as possible while extending it with new features.
Monday OpenTTD announced they will begin support IPv6 on their services:
we started making all OpenTTD services accessible over native IPv6, graciously provided by LeaseWeb for which we want to thank them. We also added IPv6 support to the development versions of OpenTTD (the nightlies and trunk) so they are capable of handling both IPv4 and IPv6 side-by-side. At the moment of writing approximately 30% of the servers with an OpenTTD version supporting IPv6 are reachable over IPv6. Even if we look at all servers 3% is reachable over IPv6 (average IPv6 penetration is around 1%).
All in all this means that 0.8.0 will support IPv4 and IPv6, although it will still take a while before we release 0.8.0, and that you can reach all OpenTTD services over IPv6, so no need for IPv4 anymore.
More infomation about OpenTTD on: http://www.openttd.org/