Virgin O'Riley, Who Knew Someone Like You, In The Mood For Some Killing, Tainted JesusGo Home Productions mashed them together nicely with "Virgin O'Riley"
Not all mashups are upbeat and fun. Sometimes they can be well-crafted and tear-jerkers. In 2011, Mashup Germany created "Who Knew Someone Like You", which I still can't listen to without tearing up.
As a palate cleanser, let's check out DJ Schmolli's "In the Mood For Some Killing", which mixes The Glenn Miller Orchestra and Rage Against The Machine (yes really):
And to get us back into pop-land, DJ Lobsterdust gives us Depeche Mode and Soft Cell together with "Tainted Jesus":