Alright so tell me if this is funny?

Tonight at the dinner table we discovered the joy of the oh so clever "Knock-knock" joke. Fortunately, half the people at the table were entirely unversed in the better known ones and therefore decided to come up with their own. This added to the joy because, well... I'm not sure if they were actually funny. Some of my favorites went as follows, Karina- "Knock knock!" Mama- "Who's there?" Karina- "Cantelope." (I'd like to point out that when she said this I could not discern what the word was.) Mama- "Cantelope who?" (I was very dutifully impressed at her ability to understand the child at this point) Karina points across the table at a bowl. "Cantelope!" Mama- "Oh, cantelope... actually darling, that's watermelon." Karina got a very contemplative look on her face and said with a grin, "Watermelon?" Grisha- "Knock knock." Papa- "Who's there?" Grisha- "Animal" Papa- "Animal who?" Grisha- "Papa!" Jonathan- "Knock knock" Gabbie- "Who's there?" Jonathan- "Interupting wampa!" Gabbie- "Interuptingwampawho! HA!" Jonathan- *gigglesnickergiggle* From this I have deduced that Karina is learning new words (and forgetting some old ones) all the time, Grisha thinks Papa is an animal, and Gabbie never grew up.