Okay, Who's the Wise Witch? (S06E25)

Darrin is working on an ad campaign for a housing development, using a scale model of the sample home for reference. When he and Samantha pick up the model to carry it out to the car, they find they are locked in the house. Doors and widows refuse to budge; Darrin cannot even break a window and when Samantha tries to pop Darrin out of the house, she cannot. Having all the earmarks at a spell, they call on Endora – who swears on her "witches honor" that she did not cast the spell. When Endora tries to leave, she finds she, too, is trapped. At this point, Larry telephones, inquiring as to why Darrin is not at the office for the important meeting with the clients. (iTunes)