It seems simple enough: find two unrelated songs and blend them together, usually by overlaying the vocal track of one song over the instrumental track of the other. This joining of different songs is called "mashing" or "blending," and it's what Pittsburgh, Pennsylvania-based electronic musician Girl Talk (aka Gregg Gillis) does best. His ability to seamlessly mash songs has resulted in noteworthy albums and high energy live shows. While his songs have been called "a lawsuit waiting to happen" - as Gillis does not seek authorization for the songs he samples for the mashups, but instead just cites the original artist--he has enjoyed success and his controversial methods only seem to garner him more popularity if anything.