The Festival of Soloni was an recurring annual event on the city/plane of Nareev. The Nareevians would gather to celebrate their (demi)god Soloni. Some of the Nareevians believed that one day Soloni, having been missing for a while, would return to them after their plane was destroyed during the change to the Fifth Edition of Magic, and save them. This prediction proved to be correct during the fifth annual Festival of Soloni, when the Ätlän-tã Fælcons valiantly assisted the demigod by clearing the shrines to him around Nareev, allowing him to return and move Nareev to the plane he had spent the last five years building for them.
Note: It's a little unclear as to when the Fifth Festival actually begins, as the episodes preceding it all take place on/around the same day, but the first time it is confirmed to be going on is...