The Day of Dev Miracles

When the moon is closest to us, light casting can become nothing short of miraculous. The illusions we create are on the verge of manifesting, and all it takes is talent to make our images become real. If we can imagine and project the image of a complete 'thing' then it can come to be during the Day of Dev Miracles. How long things created on this day will last truly depends on the mastery of the spell, but it can be anywhere from seconds to years, to number of uses before it dissolves back into light.
There are countless festivities that happen on the Day of Miracles, some that are are astounding. Renowned for hire twilight casters do very well. They are able to sell their service during this time to the highest bidder. They make a small fortune from imagining a beautifully intricate piece of jewelry that on the Day of Miracles becomes real. Some twilight casters are wise to work with others to create a more ambitious and complete vision. There are even cities that boast their origin to be a vision by a god during a Day of Miracles.
On the more feral side of the day of Miracles, the Blood and Property matches on this day have extreme cultural significance to them. Two rivals who wish to kill each other for the other's property and family, can on this day Twilight Cast a weapon. If the weapon that might appear in a flash at anytime during the combat kills the enemy, that weapon will become permanent and never dissolve into light. It is such a waste of an awesome day that comes around so rarely.
The weeks following the Day of Miracles can be the most exciting and chaotic in dev society. The nation of Kaishah, and especially the city of Khanahari- regions known for their culture of Light Magic are especially volatile with stories of success and failure, happiness and remorse. People get their dreams for one day, but so many of those dreams literally disappear in the following week. There is remorse from those whose object they cast disappears before they even use it, and happiness and ruthlessness from those who use their envisioned wish flagrantly.
The Day of Miracles in its infrequency serves as an equalizer in some way, for it is a power that any dev can take advantage of.