A Mad Idea or A Crazy Idea (German: Ein toller Einfall) is a 1932 German comedy film directed by Kurt Gerron and starring Willy Fritsch, Dorothea Wieck and Rosy Barsony.

Penniless Munich-based painter Paul Lüders goes to stay at his uncle's castle in the Swiss Alps.

His equally impoverished uncle has gone to England in order to try and sell the property to wealthy Mr. Miller.

A series of misunderstandings lead to Paul renting out the various rooms as if it were a hotel, including a large booking by the Miller Girls, a dance troupe led by impresario Theo Müller.

Despite the mix-ups, the hotel is now so successful that his uncle abandons the idea of selling it.