If you have ever listened to the Beastie Boys, you've heard people who "scratch". There are tons of DJ's out there who do this but one of the kings is a guy from the East Coast called Skratch Bastaid. When listening to his music, remember there are no synthesizers or sound machines....everything you hear is coming from two different turn tables.
Watch closely and you'll see how he switches from song to song, from record to record, without changing or interrupting the beat. Sometimes he is playing the same record on both record players but mixing them together at the same time.
If you want to get technical...his style is called scribble. All I know is I can't do that....