We all know that time constraints are the biggest challenge for Ender in developing new features/aspects of the game. I was thinking of a few contests/events that would be easy to implement, and require minimal work from Ender. A few ideas:
A "race to beat this bot" comp.
Ender wills a bot into existence, and people race to beat it. Contestant bots must have a maximum age. For example, Ender creates a bot at 12 noon, a bot must have been built no earlier than 12 noon to qualify for winning. Prize could be a free buff, or free trophy points, simple glory on a list, or anything that would be easy for Ender to bestow.
Levelling race.
Simple enough, Ender sets a time and goal, all contestants start from level 1.
Mediated wagers.
Players could wager stars for whatever they wanted to bet on, (levelling races, monthly rankings) and Ender could facilitate transfer of the winnings. Of course, it would be at Ender's discretion which bets to entertain, as only wagers with very clear terms should be allowed, to avoid problems. Typing it down, it sounds like it might take a bit more time from Ender than i thought. Hm. I don't know.
Etc.