A capella men's ensemble version of Lady Gaga's Bad Romance
EDIT: This has been great, everyone. Thanks to everyone for all the terrific links and for introducing me to a number of artists I wouldn't have heard of otherwise. Seriously, the online rabbit-holes have been thoroughly enjoyable--even it I stayed up a bit too late a number of times.
Imho, Leo is so overrated. All he does is change the instruments used to play the song, and everything else remains the same, including his voice, tempo, lyrics, style, etc.
Now this guy here, is actually impressive, and delivers the cover in different styles.