Given the lack of opposition at this point, I propose we move on to discuss implementation.
The first issue, is who will host. Someone, most likely Asterix as the Council Admin, should speak to ON or the powers that be about hosting a Wiki. If there is an affirmative answer, Sim and Mim should go ahead and set up the Wiki as per the software decision we will make.
If (and ONLY IF!) the answer is negative, we will need willing members of the community to step forward for hosting. At that point, they will obviously have the final say on Wiki software, but I would hope they will abide by the Council's decision. Furthermore, The Council Administrator Asterix will need to work out the possibility of using a TWC-like appearance and look, as well as taking the steps to integrate the Wiki with the site, if it is the decision of Hex to endorse this endeavour.
If, in the end, ON refuses to host a Wiki, and Hex refuses to officially endorse and put TWC's name behind a Wiki, I think we should re-evaluate the endeavour.
Anyway, the second issue, is software. There are dozens of engines available:
http://c2.com/cgi/wiki?WikiEngines
I have used GikiWiki and MediaWiki before, and vastly prefer MW, but I think we will need to limit outselves to the programming knowledge of the Wiki admin (Sim if ON hosts, or if it is a 3rd party, their preference in language). Sim has endorsed MediaWiki, and that is what I would suggest, as well, but feasibly any PHP Wiki software can be used. (I'm not sure of your programming expertise, Sim, but I will take PHP as a given seeing as your number of accomplishments)
If there is indeed a consensus reached by the CoW about the Wiki, then I suggest you ask Asterix to speak to the Network Admins about it.