What details of the "story" did you find funny?

I think Pip's fantastical tale about the lavish life at Miss Havisham's estate is rather humorous. Stories like dogs being fed veal and Miss Havisham lounging on a velvet couch are funny to imagine. (picture old lady Havisham on velvet...Yuck!) Pip is trying to become "uncommon" by lying about his experiences. Pip made up lies about the Satis House with the intention of glorifying it in front of the eager Mr. Pumblechook and Mrs. Joe, both of whom eat it up.