My all-time movie glitch; in "Somewhere In Time", Christopher Reeve drives up to the Grand Hotel on Mackinac Island. If you've ever been on Mackinac Island, you'll understand.
My second-to-worst glitch on TV: There was a (short lived, I think) effort at a newer "Zorr o" series. I saw one episode. Several characters spent an extended time aloft in a hot air balloon...with no heat source.
My all-time TV boner: in some series which was mercifully euthenized at an early age: A radio-controlled toy car chassis, with a camera mounted on it, used for surveilance; the good guys watching on a TV monitor; the camera was a common 35mm film camera. This was on something made and sold for regular network television.