I went to a Left Hand beer/dinner pairing event at Lucky Pie one time. The owners were there talking about each dish and each beer, actually both dishes. They put two plates out with each one to bring out different flavors of each beer. Anyways, they said they weren't all that into IPA's which is how 400 lb monkey came to be named. They were getting egged on to make an ipa and their master brewer said, "Any monkey can throw 400 lbs of hops into a beer and make an ipa." So when they made one, that's how it got it's name.