Continuity mistake: After telling the joke about the Teenage Mutant Ninja Turtles, Marshall's hands change between shots, from holding his hand for a hi-five to his pockets to holding the Skittles. (00:08:32)
Other mistake: There is absolutely no reason for Ted to hang around underneath his apartment window while Jeanette is throwing stuff out of it. Any sane person would know that there is a very high chance of getting struck by the myriad of Ted's belongings that are wantonly chucked out onto the street. He's not trying to collect/catch anything because he is turned away from the building, and is not paying attention to the items that are being thrown out.
Chosen answer: She was finally shown at the very end of the last episode of season 8, continuing into season 9. The actor's name is Cristin Milioti: http://www.imdb.com/name/nm2129662/.
Knever