The 19th annual Warped Tour is ready to kick off, and after nearly two decades the summer-long trek continues to evolve. Boss-man Kevin Lyman is a master of adapting the lineup to reflect the tastes of young fans, making the "Punk Rock Summer Camp" less and less punk rock...but the genres represented on the tour have expanded far and wide. Warped Tour offers a up-and-coming bands the opportunity to break out in a big way, while veteran groups can reach their hardcore fans. And sweating for eight hours in a parking lot, surrounded by music, is always better than another boring summer day spent at home. So without further ado, here are the 20 must-see artists at Warped Tour 2013.