"Epic" as a hip adjective is about two years past its prime and a touch hyperbolic, but if it has ever been used in proper context, it is in the following description of the video embedded below:
This guy's surprise marriage proposal is epic.
Brad is clearly creative, romantic and in love.
This is all evidenced in his proposal to Emily -- consisting of an exorbitant lip-syncing flash mob, a beach treasure hunt, an emotive video montage and an ensuing party.
Behold: the surprise marriage proposal to end all surprise marriage proposals.