While the mash-up phenomenon has existed for several years now, it is unprecedented for artists to actually team up for the songs being combined, especially those at the top of their respective genres

While the mash-up phenomenon has existed for several years now, it is unprecedented for artists to actually team up for the songs being combined, especially those at the top of their respective genres. That is what makes Jay-Z and Linkin Park's mash-up collaboration, the two-disc "Collision Course," special. The rapper and band convened in a studio to rework six tracks (on CD), as well as at Los Angeles' Roxy nightclub for a live show (DVD). The CD, produced by Linkin Park's Mike Shinoda, has more hits than misses. Some tracks, like "Numb/ Encore" and "Big Pimpin'/ Papercut," flow together seamlessly. "Izzo/In the End," however, sounds forced. And although the music generally works together, the lyrics don't always: Linkin Park's angst-filled words about relationships and Z's boasting sometimes sound incongruous. But the DVD negates any slight misgivings. The two acts are obviously enjoying themselves, both in the studio and onstage. And there's a palpable energy flowing between the band and the rapper, as if they both know that they're part of something groundbreaking.—BT