A big party should be organised by Tharg. Go on Mighty One!
Invite creators past and present, editors anyone ever involved in making it marketing it etc; celebrity fans could be invited too. Flog tickets to readers and comic fans in general. Sure they'd be plenty of intetest, especially if the mighty one got a few high profile attendees.
Somewhere like Proud in Camden maybe...
Invitations to celebs and creators would have to start going out soon though and publicity for the tickets..