I have got to say, I'm kinda bummed out by all the Lenny fatalism in this thread. It's taken me two days to read through all of it mostly because everyone seems to assume that all of the writers for TBBT just want to break Leonard and Penny up. When I first read the taping report for the first episode I thought the Tag was potentially funny, if a little stupid, but I read through this thread and suddenly I feel the need to step in and defend it.
The scene with Leonard showing the movie at the end, might come off as creepy or weird or OOC if it was done completely wrong, but I highly doubt it will. The scene is important though, because first and foremost IT IS FUNNY, secondly because the movie is mentioned as Penny's secret, and the most likely reason for it to be a secret is because she is afraid of what people (*cough* Leonard) will think of it, by having Leonard not only know about it but be willing to show it to others as an example of her acting ability shows that her fear surrounding the movie is unfounded (like most of her fears and insecurities regarding their relationship). From an in-universe perspective, Leonard is proud of Penny and her work as an actress so if he was questioned about her being an actress (because no one on the boat has seen her act) he would show whatever examples he has to defend her. Most likely there was no video of her in "Street Car Named Desire" for him to show off, and her hemorrhoid commercial is not exactly something to show off, so the best he can do is the movie which she happened to have a topless scene in. If I understand correctly the movie is apparently a slasher/horror movie so odds are the scene is not exactly played for the erotic potential anyways. Besides if it was a cheap slasher Penny could easily be the best actress or actor in the movie, which in and of itself would say something about her acting abilities (it is a whole lot harder to give a good performance in a bad movie than to give a good performance in a good movie).
Was kind of hoping my first post on this forum would be a little different, but oh well.