I had the best time tonight on MvM Manhattan with my new friends. We all agreed to play engie, and so awesomeness ensued. We had 8 engineers on a team of 10:
spawn was hilariously congested with teleporters:
Somebody had an idea after round 5 ended for us to all place our sentries at the entrance bay. I call it "The Great Wall of Sentra"

Sadly it quickly fell down once the sentry busters started coming out, but beforehand it held together really well.
Then we went and played Rottenburg a little while afterwards.
However, we eventually left 1 by 1 after a while of losing repeatedly on rottenburg (a few scouts and spies managed to slip past our defenses a couple of times with the bomb). We made sure to all add each other to our friends list before we left though!
So yeah, all in all a great day.