Sage is a classic herb--just ask
Simon and Garfunkel. I've got a bush growing in my vegetable garden, and I recently decided to try to use it in a homebrew.
Typically, sage is used in savory dishes, especially poultry dishes of chicken or turkey. Its flavor is unique, sort of peppery and bitter, but hard to define in more specific terms. It's also used for medicinal purposes, and has been recommended for treating just about any ailment you can come up with. And, perhaps most famously, sage is burned for spiritual reasons--it's smoke is considered a cleansing agent in rituals carried out by hippies and certain Native American tribes.
I decided to try to use sage in a Pale Ale. I thought its peppery bitterness might blend well with the hop-oriented nature of the Pale Ale style. Sage is an herb that combines in wonderful ways with other spices, such as thyme, and it's also sometimes used to accent acidic/sour fruit flavors, such as fruit-based vinegars. With that in mind, I figured I'd pair the sage with Centennial hops, a hop known for its citrus-like aromas and bittering qualities.
I cut five large sprigs of sage from my plant, rinsed them in fresh water, and then chopped them thoroughly. Five sprigs turned into a bout three large handfuls when chopped. I added half of the sage right and one ounce of Centennial right at the start of the boil, hoping to utilize its bittering qualities. I added the other half of the sage at flame off, to see if it would contribute to the beers aroma. I also made sure that all of that chopped and boiled sage made it into to the fermenter with the yeast. I've read that certain chemical components of sage are most effectively extracted by alcohol (also apparently true of cannabis, though I can't say I've got any first-hand knowledge of that), so putting the sage in with the alcohol-producing yeast was a way of trying to utilize that concept.
The beer is in bottles now, and won't be ready to drink for another few weeks. After making the beer I realized there's an entry for sage in the book
Sacred and Herbal Healing Beers, by Stephen Harrod Buhner. Buhner says that "sage ale was one of the primary ales brewed throughout the Middles Ages." He also describes some of its medicinal uses--everything from healing infection to inhibiting Alzheimer's disease--and he mentions that sage is known to make beer "especially inebriating." I'll let you know if I find that to be true.