Our (fairly high level) party had secured ourselves a keep in which to base our operations, but unfortunately a huge army of Githyanki had been amassing in the underworld for some unknown reason, intent on destroying us all. (Don’t ask, our DM is just plain weird).
We thought up a battle plan; we would send out our paladin on his special mount to go up to their lines, and make them chase him as he turned back and rode into our castle. We would then seal off the kill-hole section of the castle (the bit before the keep) with all the Githyanki in it, and pepper them with arrows and boiling oil until they all died, saving us from fighting.
So, we sent out our Paladin, he rode out to their lines, and he got his horse shot out from under him. He couldn’t run away fast enough in Full-Plate, so he was forced to fight them. He ended up killing them all before we even found out he was in trouble.