So, Y'know how phone and facebook games keep players by only letting them do something every few hours? or even days?
is there a mod or plugin to let players do an action, and then have it pay off for them in X hours?

here is an example:

Steve goes to a spot in his castle, talks to the assigned villager, and tells him to make a mine. 8 hours later, there is a small mine, just big enough for a minecart to go down into,and come back up exactly 8 hours later, with loot in it's chest.

there are many other possibilities, a farm, a mob fighter, a critter hunter, And so on,

you can lock it, so only you can use it, or set it so anyone can use it,

pvp server? it can be captured, Or, even destroyed, and it will take X gold, time, Levels, etc to

basically, i'd be happy with villagers who give you X every X ammount of time.
bonus would be the pvp things, and if i could get it on Bukkit