You’ve got wizards next to 1980s icons wedged between superheros with a pinch of teen heartthrobs and heck, even a splash of aliens and Power Rangers. It must be Denver Comic Con. It happens only one weekend a year: Some the biggest names in the world of movies and television flock to Denver to fill the Colorado Convention Center — and you get to meet them. Stars of “Game of Thrones,” “The Walking Dead,” “Harry Potter,” “Guardians of the Galaxy” and many more will be in town this weekend, pens in hand and smiles ready for selfies — but it won’t come cheap.