The violinist Joshua Bell has long invited different artists to his house for informal collaborations and jams. Here Bell records some of these sets with rock stars (Sting), film composers (Marvin Hamlisch), jazz musicians (Chris Botti), Emmy winners (Kristin Chenoweth) and experimental indie-poppers (Regina Spektor, on the haunting yet quirky "Left Hand Song"). It makes for a casual, intimate mood that still pushes listeners' assumptions -- Bell catches fire with bluegrass stars on "Maybe So," for instance. This is an album of pleasant surprises.