Here is a set of four Christmas carols, (O Christmas Tree; God Rest Ye, Merry Gentlemen; Joy to the World; and Silent Night.), arranged as instrumental duets.
The duets have been tabbed separately for guitars, mandolins, ukuleles, tenor guitar/banjo, and 5-string banjo. There is also a concert version with notes only, no tab, for those who prefer that format.
All versions of the duets are in the same keys, so you can mix and match instruments: Uke & guitar duo; mandolin & tenor guitar; or one gigantic string-band orchestra! (Please send us a picture if you do the giant orchestra thing.)