A few weeks ago, I came up with the idea of adding an astrology system in EL. I didn't start implementing it yet,and in fact I didn't even fully design it. I will do that on the plane, on my way to Romania for a 2 weeks vacation.
This is how it will work:
Every player in the game will be assigned a random star sign. I am not sure how many star signs there will be, probably 12. Those signs will be unique, not using any existing horoscope.
Players will not know what sign they are, unless if they go to some astrologer NPC that tells them, for a fee. That NPC will also (for a fee) tell you how the next week is going to be for you, from an astrolgical point of view.
There will be a number of planets; the number is yet to be determined, but probably around 7 or so. One of them will be the planet where everyone lives, and the other planets will influence some activity. For example, one planet will influence the defense, one will influence the chance to get rare items while you manufacture things, and so on.
Each planet will orbit around the sun at a different speed, just like in the real life.
Depending on the angle between the planet everyone lives on and the planet that influences a certain activity, and the star sign of the individual, a chance will be computed for each action.
I might even implement a moon, and the phase of the moon will weaken or strengthen the effect.
This whole thing will require a lot of math (especially trigonometry), so I'll make sure to bring some formulas with me on the plane, as I won't have internet access during the plane trip.