Depending on where you are and what condition the land's in there are LOADS of things you can do !
It's better to get it now, than find in a few years you're wishing you had done
As for what to do -
rent it out to local farmers
rent it out to horse owners (if you've any way to provide stables/field shelters you'll get a premium rental)
Plant it with trees (financial return a few years down the line)
Raise some livestock (though will need much more involvement and higher initial outlay than the other options)
Like Julie says - you can NEVER have enough land