The other day I was picking up my mandolin and guitar from the local store (winter set-up time) and while at the counter I saw a new CD from the Let's Jam series. For those not familar it's backing tracks that you can play to...they have rock, blues, jazz, metal, bluegrass and NOW...Acoustic...Unplugged...It's a lot of fun and it's easier for the mando to cut through than the ones where electric instruments are employed. The downside is all of the 17 tracks (which give you plenty of time to play) start with a percussion pick up...it gets a little tiring and one of the blues tracks does not include the intro turn around...but it's not hard to figure it out...
The styles range from country to blues to funk to rock and I'd recommend it to anyone who is looking at exploring improv...