>In the studio, John Mayer comes across as a technically proficient singer, songwriter and guitarist, although he can sound somewhat emotionally removed from his material. But on this two-disc live CD set (a DVD is sold separately), he proves he's not just another easy-listening singer-songwriter with a better-than-average knack for the blues. The album features three separate acts — acoustic folk, power-trio blues and full-band rock — and Mayer lets his guitar go anarchic on each one. It's clear that he's really feeling the music when he launches into the protest R&B of his 2006 hit "Waiting on the World to Change," and when he quotes a few bars of Otis Redding's "I've Got Dreams to Remember" before segueing into his own soulful "Gravity." Groupies will swoon over the opening five-song acoustic set of lightweight favorites like "Daughters," but it's when Mayer trots out the power trio that his blues licks get red-hot, peaking with the squalling, 10-minute guitar workout "Out of My Mind," where he conjures Hendrix not just in the riffage but also in the question he asks his audience midway into the song: "Can I play my GIT-tar? Can I play it loud?" Easy listening? Not this set.

“Help Me”

Joni Mitchell wrote and recorded this song for her album Court and Spark, but she had to switch from her regular band to make the song sound exactly the way she wanted. "I had attempted to play my music with rock & roll players," she told Rolling Stone. "They’d laugh, 'Awww, isn't that cute? She's trying to teach us how to play.'" Mitchell switched to a jazz band, Tom Scott’s L.A. Express, and scored the biggest hit of her career in the process.