Fresh carrot juice, the world's best tonic. Sweet, rich, and creamier than you'd expect.
Drink a nice big glass of it; half an hour later you'll feel on top of the world.
A couple things to keep in mind:
First, use organic carrots- usually the ones with greens attached are good and sweet. I avoid bagged organic brands like Bunny Luv; while they can be fairly OK once they've been cooked, when raw they often yield bitter juice.
Second, drink carrot juice within ten minutes- a lot of the good stuff breaks down quickly, also the juice oxidizes to an unattractive brown color. Acidifying with lemon juice prevents the color change but doesn't preserve the full magic.
Third, combinations work well- you can add an apple or orange, or some parsley or dandelion greens, or a few ribs of celery, or a beet. But I suggest trying pure carrot first, for the full effect.
Nothing picks me up like fresh carrot juice.
Bunny-Luv organic JUICE carrots are actually perfect for juicing; they're the right size, have a high juice-to-carrot ratio, and they're delicious; virtually every serious juicer I know who has access to them uses them exclusively, including the folks at Norwalk. And carrots should be topped, tailed, and peeled in order to yield delicious juice that keeps; I can only think that your using the greens is what's turning your juice brown (orange+green=unattractive brown) because in 23 years of serious juicing I've never had that happen to carrot juice, even in the days before I learned I should peel them. And no, you're not cheating yourself nutritionally by peeling carrots, beets, and parsnips.
Fourunder, The Juicing Book by Stephen Blauer is a terrific introduction to juicing and has some slammin' recipes that are yummy as-is and will probably inspire creative tweaking on your part. It's not expensive and is available on Amazon. I suspect it'd fulfill your needs to a T.