Blast off with the Robinsons

Check out “Lost in Space” fans’ episode-by-­episode ratings on the Internet Movie Database, and you’ll see what begins as a hip 1960s sci-fi series spiral into Saturday morning inanity — even though it never left prime time. But that endearing campiness is exactly why the 50th-anniversary Blu-ray, the 18-disc “The Complete Adventures” (Fox, $200), is such a blast. With all 83 episodes remastered in high-def, you can almost see the strings behind the cheap special effects and sets. The loads of extras include cast commentary on some episodes and a reading of a script that updates the space-faring Robinson family’s adventures. A shoo-in for baby boomers’ holiday wish lists.