One of the greatest things about the Beatles was the Fab Four's willingness to experiment, blending all kinds of subgenres into their pop-rock palette. Willing to borrow from blues, folk, orchestral, psychedelia and other eclectic influences, the collective work of the Beatles maintains a timelessness that can withstand any kind of interpretation. Putting this concept to a serious test is the trio Beatlegras, which has made a solid living delivering surprisingly skillful renditions of such favorite tunes as "Come Together," "Please, Please Me," "Can't Buy Me Love" and "Blackbird," all with a bluegrass bend. Returning to Richmond, Beatlegras performs at the Cultural Arts Center at Glen Allen on Friday, April 8, at 7 p.m. $25. 261-2787.