The rock instrumental has the unenviable task of grasping the listener's attention, and then keeping it, without relying on words and catchy choruses to do so. Done poorly, the tune feels repetitive and tires quickly. Done right, and it stays with you, each chord as memorable as any song lyric. Whether it's the work of a guitar virtuoso like Eddie Van Halen, or the combined effort of a trio of musical wizards like Rush, the great rock instrumental is a rare and beautiful thing. Here are ten of the best.