It wouldn’t exactly be the holidays in Middle Tennessee if some theater company or other weren’t offering a production of this Yuletide standby. It’s not exactly the Southern answer to It’s a Wonderful Life, but creators Jaston Williams, Joe Sears and Ed Howard successfully exploited the small-town Texas rhythms of their original Greater Tuna — first produced in Austin in 1981 and still going strong nationwide — and moved it on over to Christmastime, wherein the residents of Tuna (the Lone Star State’s third-smallest town) contend for honors in the local Christmas Yard Display Contest. A Tuna Christmas debuted in 1989, and 23 years later it’s become a cornpone comedy tradition. Encore Theatre Company does the honors here, right near the border of Davidson and Wilson counties. Hugh Britt and Bowd Beal enact the 20-plus goofball characters, from Vera Carp and Farley Burkhalter to Bertha Bumiller and R.R. Snavely.