I propose to play a game (or, perhaps, even a series of games) where the goal is to finish in the shortest amount of real time instead of the smallest number of turns.
The sentiment behind limiting RT would certainly seem to fit a familiar theme, one I know our current setter is very conscious of. Coming to mind I think of: more smaller maps, limiting numbers of cities (especially the limit of one), and stopping when an intermediate target is reached - such as that one where we had to deliver one freight between each pair of our four cities.
And it is true that the core group for GotM is not now very big - maybe there are five of us at the moment. There are a few silent partners who intermittently submit games, and we occasionally enjoy a visit from experienced and talented others - such as yourself Professor. Also veteran Civ2 enthusiasts wander by, but myself and the Major were probably the last of those to stay, and that was a couple of years ago now.
Of the current three active games two have limiting RT in mind - 145 is OCC and 146 says no cities on the main land masses.
Counting and maybe scoring RT would be a step further. I would share obvious concerns about moving too far from what sustains the current core group, and I think we are agreed that mixing things up with the games is the best way, but I would try and support a one-off.
I have never tried a game like that, and maybe I am being ambitious or naive, but I would expect it would go very much quicker than is my usual way.
I think a simple record of the game is needed because the point of a GotM is to have something fun to discuss. I will try and fit with any guidance offered. We might all also want to make saves at specific times (every hour?) that can be checked later.
I think the time should be from first loading of the game save file to the display of the results screens.
But the usual game definition info is provided to allow unlimited pre-planning before first loading e.g. difficulty level, civ, number of opponents.