Video game retailer GameStop has announced plans to buy Geeknet, the Fairfax company that runs the popular ThinkGeek website, in a $140 million deal that’s expected to close this summer. ThinkGeek specializes in goofy and nerdtastic merchandise from Star Wars, Star Trek, Doctor Who, Marvel and other franchises that appeal to adults and kids alike. (Theoretically, at least, these are the same people who like to shop in GameStop’s stores — and will be thrilled to check out that Captain America Stealth Shield Watch in person.) Apparently geek chic is worth a lot these days: GameStop expects this acquisition to boost its sales by $100 million per year.