Tragedy is taking all the hits of yesteryear and making them metal, but doing a really good job with it. A perfect example can be found above, with the group's cover of The Bee Gees' "Stayin' Alive." All the melodies are there, the vocals are gloriously all over the place, and the instrumentation really allows the cover to take on a life of its own.
You really ought to grab Tragedy's cover album The Joy Of Sex here.