Good post in the makings. There are so many different recipes and what have you to DIY CO2. Let's use this post to see what everyone else is doing.
Here's mine...I use the Jell-O method.
Step 1:
Using the big box of Jell-O (any flavor .... not sugar free) (6oz) / 2 1/2 cups hot water / 2 cups sugar / dissolve and refridgerate over night
Step 2:
Take 1 cup hot water and disolve 1/2 tsp sugar.
Add 1/4 tsp yeast to activate (~15 mins).
Cut Jell-O in cubes or rectangles and add to bottle. (BTW...I use the Ocean Spray bottles as opposed to the 2l soda bottles. I find these get you a better seal.)
Sprinkle 1/4 tsp baking soda on top of Jell-O.
Pour yeast mixture into bottle
Fill bottle with warm water up about 2" from the top.
Sprinkle 1/4 yeast on top.
Cap tightly.
Within a couple of hours.....bubbles in the tank. Lasts a very long time.
Bubble flow decreases..recharge..pour out watery mix (leave remaining Jell-O) in bottle. Add warm water and 1/4 tsp yeast.
Next up for me will be to try the Jelly method. ;o)