"False Witness" probably won't be remembered for the case--the disappearance of a Navy witness which leads to a DA keeping a secret, a murderer trying to help his daughter, and a guy who wants revenge for his sister's death--but it could be a turning point for Tony as a character, assuming the writers follow through.
I kept thinking that Tony being serious was all a game. This wasn't the first time he's pulled a long prank, so I was expecting a big kicker somewhere. When Ziva confronts him about it, however, Tony tells her that a girl he can a one-night stand with a year ago recently got into a car crash because she was depressed. Whether Tony was the actual cause, he takes it hard upon himself and decides to shape up. But as Ziva reminds him, he is the class clown who everyone loves, and has to balance his behavior, not tilt in any direction. By the end of the episode, he regains his funny side and pulls a massive joke on Ziva, inducing her to even pull out her gun. We'll see if the writers do decide to tone down Tony's antics in future episodes, or whether this is a one time deal.
Score: 8.9/10