Sessions 13-16 of New Dawn involves, well, a lot of complicated stuff.
The PCs are rescuing their Gods from an extra-dimensional prison while at the same time undergoing tests of faith to demonstrate their worthiness to act as servants of the Gods. I did a lot of deliberately weird stuff, like combatants fighting while standing on the walls or ceiling and a bunch of Portal (the video game) style portals in a room filled with ice and fire. It was a lot of fun, and also the payoff for a bunch of subtle clues I'd been setting up since the start of the campaign.
http://noschoolgrognard.blogspot.com...ecrets-of.html