The Call to Action events are very new to Rift, so new that not all of them have even happened yet!
The call to action events are small ‘long weekend’ events where you farm currency by doing dailies. The currency is used to buy different mounts that are only available from these events.
Call to Action events used to run back during the Storm Legion and Nightmare Tide expansions.
Each event was completely separate and came with its own currencies.
During the summer of 2018 the events had not run for around 2 years. The Devs decided to update them and bring them back. They combined all the old currencies to a singular one called ‘Chaos Motes’.