In this case a "moment" can be an incident in a show, an episode of a show, or a show itself...but mostly the first two. I'm going to offer an observation and suggest that "moments" tend to occur most in live situations, and in non-scripted but edited shows (reality shows). I mean sure, series give us cliffhangers but when it comes right down to it we know that whatever catastrophic event happens at the end of the season, the writers are going to make sure that most if not all of the results will, on the whole be superficial changes at best. So with that as a base, here's what I've got.
Final episode of The Amazing Race 7 - Uchenna & Joyce come from having no money and being last to beat Rob & Amber. Their victory is made possible when a jetway that has been retracted is extended again to allow Uchenna & Joyce to get on the same plane as Rob & Amber.
Tarantino directed episode of CSI - Yes I know this goes against everything I said above, but this was one of the most talked about episodes of any TV series of the year. It's also one of the few episodes of any series that I know of which has been offered as a stand-alone DVD.
ABC's memorial to Peter Jennings - A two hour event that was offered commercial free and was an amazing study of Jennings's life and dedication to quality in journalism. One of the best biographies of a TV personality although the dedication to quality in journalism it represented was undercut by the fact that ABC's News Division was running an ongoing series about online dating that was more fitting as a reality series for the Entertainment Division.
Kanye West on the NBC Katrina benefit show - "George Bush doesn't care about black people."
Randal tells Trump he should not also hire Rebecca on The Apprentice - Given the way the two had interacted over the previous weeks and just how close the final task really was, Randal's statement and his attitude was a real shock, particularly if you really accept that the show is a job interview rather than just a game. That is to say that if he's serious about being Trump's employee he should be willing to advise him to hire a qualified person that the boss is interested in. Instead he couched his response in terms that were related to the show.
Tom Cruise on Oprah and The Today Show - The destruction of the star's reputation will be televised.
Feel free to comment and add more options here.