Found this super easy recipe online somewhere. I'll post the link when I get a chance to look it up again. I was impatient and just used bread yeast, but I bet proper brewing yeast would be way better.
1/2 lbs fresh ginger, coarsely chopped
2 cups of turbinado sugar
Juice of two lemons.
2 quarts of boiling water
1 tsp champagne yeast
Combine first 4 ingredients in a large jar and stir well. I used a large pot.
Let it steep until it becomes lukewarm.
Add yeast. Cover with a loose lid or plastic wrap (not air tight).
Let it sit 24 hours in a warm place, e.g. The oven with the light on.
Filter and bottle. If you want carbonation, set it out for another 24 hrs. Don't use glass for this, unless you want to risk lacerations :)
After its nice and carbonated, store it the fridge. I'm really digging on just using it everywhere I might generally use soda.