The Outlander track for ScavLab. Designed to support thousands of concurrent players sliding up and climmbing back up. The final demo had ~4500 players: https://www.pcgamer.com/uk/9000-player-games-are-right-around-the-corner-and-heres-what-one-looks-like/
Sadly this part of the track was never properly opened to the public nor did I ever get a huge amount of polish time; but It still was a lot of fun to put together. Building a double loop of a splitting track for players to slide down and a trio of maze-like zones for players to explore on the way back up was a fun challenge in getting intresting player flow; and letting players watch their fellows race up and down. It was key to have it fork both ways so player flow would not be too congested, but to also allow players to jump between branches so it felt interconnected.
Thankfully the team at Midwinter had already amassed a fantastic library of parts to use so putting it together was a lot less painful than It could have been.