Check out lemon balm!
http://en.wikipedia.org/wiki/Melissa_officinalis
As the name suggests, this is a calming drink. It’s related to mint but I find this more uplifting than mint because it smells so lemony. Lemons smell cheery to me. And if you let it sit in the water for hours, it draws out more menthol. Mmmmenthol! Overall, it tastes like mint and lemons. Mine also tastes like cooked greens cause I used fresh leaves and boiling water. I’m too lazy to dry it for the winter. It’s great iced in the summer too. It’s mild but very satisfying. I’m sure it’s more flavorful dried. :)
And you can all grow your own! I bought one plant a few years ago and now its growing all over the place in the weirdest locations. It’s sprouting the cracks in the concrete. You can’t kill this stuff!