A form of power/speed metal popularized on the tracking scene with musicians such as Guardian M.C., Skaven, and Claymore, as well as in traditional music by such artists as Thy Majestie, Power Symphony, Blind Guardian, and several others. Also less commonly known as neo-classical metal, because of its classical elements.
Epic metal is characterized by lush keyboard instrumentation, brasslike electric guitar lines, and lyrics that usually describe a story set in a medieval-like fantasy atmosphere (some, like Blind Guardian and Thy Majestie, even make whole albums that tell a single story). Some other common elements in Epic metal include vocal-less tracks, large vocal harmonies (Blind Guardian's lead singer sometimes layers his voice as much as twelve times, and Thy Majestie even has a live (!) back-up choir), usage of acoustic guitars, and sometimes even traditional instruments (like violin or recorder).
Epic metal is called by dozens of names, but thankfully, there are plenty of awesome amateur and indie artists that post their music free on the internet, and the tracking scene is laden with dozens of metal artists.