Ray Shepard & David Messersmith during their first visit to Snow’s BBQ in Lexington. (Photo ©Chris Wilkins/Texas BBQ Posse) Among the wonders of the world, it probably doesn’t rank with Machu Picchu or the Great Pyramid of Giza. But in the world of Texas barbecue, nothing compares to a trip to Snow’s on a Saturday, the only day the joint is open. It’s a rite of passage for lovers of smoked meat. Soon after Posse co-founder Chris Wilkins posted a Facebook photo from our recent visit to Lexington, a commenter wrote: “Can’t wait to get out there for the first…