What to do with all this lemon juice?

Our lemon tree has been dripping with lemons for a couple months now. Sure, we go pick a fresh lemon when we serve salmon, or when we want to freshen up the garbage disposal (quarter a lemon and drop a one or two pieces into your disposal with the water turned on, that's guaranteed to get rid of any funk). But my husband went lemon picking today (again) and gave a dozen lemons to one neighbor, another dozen to another neighbor, and then picked me about 40 lemons to juice. I can still see at least 40 or 50 more lemons here from my window, and I know there are probably 100-300 more where I can't see them. This tree is crazy.

As I understand it from Alton Brown on the Food Network, citrus zest can be frozen. So I have zested 18 full lemons. I'm bored with zesting and refuse to do anymore of it for now. But they're in little Ziplock baggies in my freezer, waiting for a lemon scone recipe, or maybe to be thrown into a future vanilla cake mix to give it some zing.

But can I do with all this lemon juice? I have juiced all these lemons, as opposed to just tossing them in the trash can. I don't want anyone to tell me to make lemonade, because frankly, lemonade is just too sugary for my taste. We occasionally use pineapple juice or citrus juice in a steak marinade, so we could adapt and use lemon juice instead (I assume). But what else to do with 2 gallons of lemon juice? And that's just two gallons from today, portioned into ice cube trays, Ziplock bags, and Gladware. There's still a ton left on the tree and I really don't want to waste it!

What can I make with lemon juice?