The CD half of this CD/DVD package (the DVD wasn’t offered for review) offers a few Sugarland favorites, but most of the tracks are chosen from the many quirky cover songs that have become a staple of the duo’s concerts. Jennifer Nettles and Kristian Bush certainly find the rollicking bluegrass number hidden in Beyoncé Knowles’ pop hit “Irreplaceable,” and the tantalizing snippet of R.E.M.’s “Nightswimming” makes for a lovely intro to their own “Joey.” But the nagging question remains, regarding not just Sugarland but most other arena-level country acts: We know it’s fun to rock out, but why not cover a country song every now and then?