Imagine you can trigger a blood moon by bringing 4 thralls to a certain spot, within a certain time frame, do some kind of steps and sacrifice them causing the next risen moon to be one of blood.
* Craftable Ritual Sites that you can place anywhere including outside of your territory. They would decay before long, you could only have one active per Vampire, and building a new one causes the former to immediately decay. There could be different types of ritual sites like Bone Altar, Pentagram, Cauldron, Ritualistic Fire Pit, etc. Each type of site used with different schools of magic and used to manifest different varieties of effects.
* You bring specific reagents to a Ritual Site, do whatever actions the ritual requires, such as igniting the Fire with Chaos Magic after the Reagents are in, and it causes humans within a radius of the ritual to go crazy and begin fighting each other.
* Books and puzzles found within the world that detail the rituals that exist as well.