A SPEND/PAY event (~twice a month, ~10 days). Buying gems adds experience to a cake; cake level-ups give rewards. Only BASIC (directly purchased) Gems count -- bonus gems inside packages do NOT (a $4.99 pack counts only its 1,000 basic gems). Cumulative Basic Gems per cake level: Lv2 5,000 (~$20), Lv3 25,000 (~$100), Lv4 50,000 (~$200), Lv5 87,500 (~$350), Lv6 137,500, Lv7 200,000, Lv8 275,000, Lv9 375,000, Lv10 500,000 (~$2,000). Unique for offering things not in normal event packages: Civilization Equipment Scrolls (Lv4 ~$200 and Lv10), Duty Officer Equipment Scroll (Lv8 ~$1,100), plus a buffed decoration and Epic Generals at Lv10. Mechanically like Ekaterina's Garden but far more expensive. Buying 200,000 Basic Gems unlocks the ROYAL Party (next tier, gems carry over): Royal Lv2 238,000 up to Lv7 1,250,000 (~$5,000). NOT F2P-viable -- purely a whale/coiner spend track; the practical target for most is the Lv4 civilization scroll. For a bot: this is a spend-timing event, not an action-scoring event -- no gathering/training/building earns cake experience, only real-money gem purchases. A mostly-F2P bot should ignore it.
Original research source: Evony Guide Wiki