This is really not specific to the Sponge client or any client for that matter but I don't really know where to put it.

Would you consider making it possible to create challenge/leaderboard type achievements where you can define something like this:

• Track-specific criteria over a specific time period (day, week, month, etc)
• At the end of the time period, X number of players with the most and/or least criteria can be awarded the achievement

So I could make an achievement like "Weekly PvP champion" or interesting things like that.

In the case of "least" tracking you'd have to be able to track another requirement for eligibility to prevent inactive players from winning so that may be hard to implement and/or use.

Probably now that I think about it the best way to use the least type criteria would work best as a "least/deaths per hour with mix x hours played" kind of requirement.