Ok, that was embarrassing.
The fighter attacked the wounded Ape with full power attack, obliterated it, and cleaved into the second ape, for a ton of damage.
The sorcerer zapped the 2nd ape (now wounded, down to 17 hp) with her Scorching Ray, but couldn't quite kill it.
The cleric came back and cast a targeted Dispel Magic on summoned Ape #3-- poof.
The remaining Ape made a valiant effort to do SOME damage before it was killed... but no.
Basically they mopped the floor with my Apes in about 2 rounds.
I forgot about Cleave...
I did have the satisfaction of watching them trigger every other trap on the level, but alas, not even a single death tonite.