Did you know, that the kids on HIMYM were held to strict secrecy because they taped the ending of the show in the beginning because they were 8 years older and didn't look like the kids their dad was telling the story to.
*Side note: When asked, later when the show finally ended, the two kids how did they keep it secret for so long? They said they had been so focused on their own lives with college and starting careers they truly forgot about it.