Another of the films from my childhood, The Time of Their Lives is a good family film and will let the young'uns see Abbott and Costello up close and personal, since they may have seen only their caricatures up till now. From the IMDb:
The film is set in the Revolutionary War period and then in 1946, with Costello playing the same role in both parts, and Abbott playing different roles (although the characters are related, just spread over 170 years!). There are a lot of funny sequences, but the historical angle makes the rest of the film very interesting in its own right. With appearances by such b-movie stalwarts as Kirk Alyn and Rex Lease, a fine supporting cast, and good-looking historical settings,the film is handsome looking and holds up well today. THE TIME OF THEIR LIVES is a nice change-of-pace for the Abbott and Costello fan, and once again shows that Costello was capable of carrying an entire feature film himself--and that Bud Abbott was excellent in character roles, not just as half of a comedy team.
My father told me that this was the first film that he saw with my mother after they were married, so it holds some personal significance, but it is certainly worth watching on its own. Two thumbs up.