How about establishing a new professional sports league!

Just imagine! We could have statistics, end of year awards (Most Valuable Letterbox(er), Rookie of the Year, LBer of the Month...), establish regional divisions, keep a daily standings of some sort, perhaps hold an all-star game, have Topps Corp. design a series of Letterboxing trading cards (include a stick of gum in each pack), build a Hall of Fame, wear uniforms, get corporate sponsorship and product endorcements!  It would be America's pasttime!!!...nah, it's already been done.