In Odenville in a quest from Aaron Edgars there is a quest called zombies in hot pursuit. You must go into a cave, click a pile of rocks in the ground then the zombies come to take your bait.
The trick is to kill them before they reach the end of the tunnel to take the bait. They will continue to spawn until you let them take the bait. They are also very slow and easy to kill, making this a great spot to kill for xp.