I was at a party last night, one of my mates is heading off to Glasgow, and it was his leaving bash. There was a guy called Dan who was providing the music, he had a set of decks and a mixer but no records. All his tunes were stored on an ibook running final scratch. There are two 'special' vinyls which sit on the standard decks, you select an mp3 and then manipulate the record and what you do to the vinyl is reflected in the sound, ie scratching, stopping, mixing etc.
I had heard about it a while back, then it only ran on Linux, but the Apple version has been released, and it is a fantastic piece of kit. No more lugging record boxes stuffed with heavy vinyl, just turn up with your laptop.
It also means you can keep original copies of all your music back home, just rip it to mp3.