18 years have passed since “That ’70s Show” wrapped up, but it’s still one of those shows I find myself revisiting frequently. Streaming services make it easy for me to do so whenever I want. The Fox sitcom launched the careers of some big names, like Ashton Kutcher, Mila Kunis, Wilmer Valderrama, and Topher Grace. In his recent memoir, “An American Story: Everyone’s Invited”, my old buddy Wilmer opens up about his time on that teen comedy. He dishes on our friendly rivalry with Kutcher and shares some behind-the-scenes secrets about filming in front of a live audience.