This is probably the best drink I have ever had that has nothing but good in it and is STILL no calories, in short to make this drink though first you need to pay a visit to your local Starbucks.
Starbucks is the only dealer that has Tazo's Vanilla Rooibos tea at acceptable prices, if you go online you can also get it but you don't get nearly as much for the price. First get some sort of size of drink at Starbucks, or buy a box of Vanilla Rooibos tea (Costs about $7 and gives about approximately 10 17-liter drinks). Ask for no milk in the tea if you buy it freshly made at Starbucks.
Buy some "Stevia" sweetener at your local grocery store, it's a bit expensive and prices vary from $5-$20 depending on size of the container and buy "Saigon Cinnamon" which is relatively inexpensive (About $1-$10 depending on amount).
Now that you have all the ingredients, put a minimal amount of stevia in the tea, it's very potent in "sweet" flavor and then add in quite a bit of the Saigon cinnamon, doing this will make the drink go from plain tasting, to better than Dr. Pepper (or other drinks of great flavor) in my personal opinion.
Summary
1. Buy Vanilla Rooibos Tea from Starbucks or online.
2. Buy Stevia and Saigon Cinnamon powder.
3. Mix the stevia and Saigon cinnamon with the Vanilla Rooibos tea.
4. Taste liquid heaven.