I am going to play some Beat Saber in ~20 minutes with a multiplayer lobby, if anyone wants to join.

How to get custom songs to work in multiplayer:
1. install Mod Assistant: https://github.com/Assistant/ModAssistant
2. through Mod Assistant install: BeatTogether, ServerBrowser, SongCore, BeatSaverSharp, BeatSaberMarkupLanguage, SiraUtil,
3. install MultiplayerExtensions from https://github.com/Zingabopp/MultiplayerExtensions
In Beat Saber to join a game by lobby code select "Online" in the main menu, switch "Playing on" to BeatTogether, "Join via code".