Here's how we did it:
The culture bomb granted us a huge deal of control over the territory to the east of Speaker. While we used those borders to strike at Lewwyn first, Speaker noticed right away that it opened up a possible play against Shoot the Moon as well. The key tile here is the peak tile at the extreme edge of our cultural control. That peak tile grants us vision over a huge amount of territory, since peaks effectively let you see one extra tile further. The peak lets us see inside Shoot the Moon's city, and we noticed that Maurice Levy was lightly defended. There was one archer when we used the culture bomb, up to two archers when we planned the attack.
Shoot the Moon probably thought he had plenty of warning for any attack, and he would indeed have had a turn's warning in most normal situations. EXCEPT that we have an India player on our team, and that means that Speaker has access to Fast Workers. Just as we used Fast Workers to set up the attack on Lewwyn, we used them again to strike against Shoot the Moon.
The attack itself was pretty simple. Road the one non-jungle hill tile with Fast Workers, road the flatland plains tile with normal workers, then move one tile with knights and hit the city. Note that Shoot the Moon couldn't even see the stack that Speaker was accumulating in his territory, since vision was blocked by that line of peak tiles. This was a true strike in the dark.
When Turn 135 started, we moved the workers forward and roaded the indicated tiles. Speaker now had 3 knights to work with: our Great General knight with Combat 3, a new knight with Combat 1, and an injured knight with Combat 2 at about 75% health. Against archers, we had something like 99.7% and 98% odds for the two attacks.
This is why knights are by far the strongest units available in medieval. Highest base strength and two moves. Since they also upgrade easily to cuirassiers/cavalry, there's no reason not to build them in huge numbers.
Maurice Levy had to be razed, of course. As awesome as that spot would have been, the odds of our team being able to hold the area were not good. However, since both knights won their battles easily, the third knight was still available to go clean up a break of good fortune: three Fast Workers moved together onto the forested hill next to the city. Three free workers? Yes, please!
Because Speaker was the one doing the capturing, they all turned into normal workers upon capture, but it was still a very nice added gain. Speaker moved up a mace and spear to cover the knights defensively against counter attack, should it come. We do still need to see how Team 3 responds when it's their turn. For the moment though, we took out a pretty decent city, three workers, and two archers at no cost to our team.
Earlier, when we couldn't build Mausoleum due to forgetting pre-game rules, we decided to use our extra Great Scientist on an Education lightbulb (instead of a 9t Golden Age). That got us the tech a little faster, let me start on a university in my silly cottage cheese capital, and should have effectively locked up Liberalism. Free tech due in 3t now, we'll grab Nationalism, and I'll start on Taj in my capital. Speaker will get a free Great Person from his Great Library build in another dozen turns or so, and we'll use that for double Golden Ages for my civ. No enemy teams have discovered any techs recently, so we are really starting to pull ahead on tech...
The one danger remaining in the game is losing cities to enemy attack before our huge research advantage can fully manifest itself. sunrise's capital is the biggest danger spot, since it can be attacked fairly easily by Team 3. I'm also somewhat vulnerable in my west, although I have pretty decent sentry coverage there. We need to keep our cities alive for another 20-25 turns and the game will be effectively over. It helps that this map is extremely defensive, and attacking is super tough.