Yonder Mountain String Band will perform five nights at the Boulder Theater on December 27-31. The group has just announced that Friday the 30th has joined New Year’s Eve as a sell-out but tickets do still remain for December 27, 28 and 29. Yonder has previously revealed that Futureman, Darol Anger, Rushad Eggleston and Andy Hall will share the stage over the course of the run. However, in a message just posted by Ben Kaufmann, the Yonder bass player suggests that the evenings on which the four guests appear will remain a secret. Kaufmann also takes the opportunity to bang on the piano as well, which you can see in the video above.