Tis the season when Chicago’s stages give way to Ebenezer Scrooges, George Baileys and Nutcracker princes — plus, the sounds of klezmer, flamenco, bluegrass and Motown.

Your kid has a toy remote control fire truck. You have an RTL SDR. See where this is going? [Jacob] couldn’t resist tearing into the why and how of the truck’s remote control protocol. The entire ...