Before the Colorado Rockies were a glimmer in Major League Baseball’s eye—heck, before MLB was even a thing—these guys ruled the Colorado baseball scene. Well, not these guys exactly, but men in the same kind of baggy uniforms. The Colorado Vintage Base Ball Association adheres to the style of the sport played in the 1860s, when the first organized team sprang up in the Colorado Territory. Today, 80 players on four squads pay tribute to Centennial State history by following antiquated rules, dressing up, and adopting 19th-century team names, such as the Denver Blue Stockings. “It’s Civil War re-enactment for baseball fans,” says commissioner Tim Stabbe. The CVBBA will celebrate its 25th opening day on April 1 (six days before Coors Field hosts its first game of the year) at the league’s home park in Broomfield. Admission is free, so it won’t cost you a thing to watch history repeat itself.