The Ghost of a Saber Tooth Tiger is one of many bands featuring Beatle scion Sean Lennon. (This one costars his girlfriend, the model Charlotte Muhl.) Lennon had a great 2010, producing an awesome album by his mother, Between My Head and the Sky, forming a very promising label, Chimera, and spearheading BAM's Yoko Ono concert-tribute. Tonight, Lennon and Muhl show off the Ghost's new album, Acoustic Sessions—an amiable collection of ballads to be followed by a rock album this year. Also: A special guest is promised. Ooh.