Inga is a maid employed by Calvin Fischoeder at his mansion. She is mentioned, but not seen in "The Oeder Games" where Calvin brings up the point that she's been secretly tossing the garbage in the hedge maze instead of walking it to the curb while he directs other tenants playing his water balloon fight to Bob who is in the maze. Calvin later mentions that he intends to watch World's Craziest Car Chases with her when his water balloon fight ends at sundown.
She gets mentioned again in "To Bob, or Not to Bob."