Both epic and fun? I dunno, the songs I consider epic are usually very serious and emotional... This is the only one that comes to mind that I find epic and fun, and I doubt anyone here would like it. http://www.youtube.com/watch?v=ZmjVeiXd3MQ
Metallica! Anything by Metallica with one of their EPIC mind-numbing solos near the end is just pure *awesomeness* I love 'One' and 'No Leaf Clover'. Their cover song 'So F**king What?' puts me in a good mood everytime I listen.
VNV Nation's "Airships". Starts off slow but it builds up eventually. The lyrics are pretty good, as well. Here's a video with the song, it's not an official one though: http://www.youtube.com/watch?v=oUJ6UMhMguY
Rhapsody of Fire: The Magic of the Wizard's Dream Nightwish: Seven Days to the Wolves, Meadows of Heaven, The Kinslayer, Wish I Had and Angel, The Siren, Bye Bye Beautiful Hammerfall: End of the Rainbow, I Believe, Crimson Thunder, Dark Wings Dark World Blind Guardian: The Whole Nightfall in Middle Earth CD, And Then There Was Silence, The Bard's Song Kamelot: Abandoned, Anthem, Love You to Death, Blucher, The Human Stain,