I accept your offer to join your tunnel digging club. When/where are the meetings? Do I need to bring my own shovel?
Did you have an activity to turn a log into a paddle?
Two main characters were meeting after-school to dig a tunnel, although their motivation was a little bit deeper (sorry, I couldn't help myself) than just digging itself.
…just be careful. There’s a man in the middle of the tunnel who will try to take your stuff.
https://www.thoughtco.com/the-channel-tunnel-1779429
so that the two tunnels meet in the middle ...