The original cast of "Beverly Hills 90210," before Luke Perry was added post-pilot.

Credit: FOX

Today, as various corners of the Internets have no doubt made you aware, is 9/02/10, the one date per century that celebrates both the world's most famous zip code and the two TV shows that were set there.

I was reluctant at first to do any kind of post on the day, if only because I'm ashamed to admit how long I watched the original "Beverly Hills 90210." But I couldn't resist doing a quick post to bring up my favorite bit of "90210" lore.

When the show began - in a year, by the way, filled with other high school shows, all of which were considered better bets to succeed than "90210," including a horrible musical called "Hull High" - most of the significant characters were in their junior year, while David Silver and poor, doomed little Scott were freshmen. The grade thing was made explicit on at least a few occasions, once in an episode where Brandon dated a teenage mother who was in the senior class. (And, yes, I know all of this from memory. Again... shame.)

Then the show became a (relative) hit for FOX, and the network both renewed it and asked for a batch of episodes to air over the summer, in which Brandon got a job at the Beverly Hills Beach Club during summer break. So when new episodes began in the fall, most of the kids should have been seniors, right?

Nope.

It occurred to the producers that they didn't want to have to graduate the bulk of their cast after only two seasons, so in the fall episodes, Brandon, Brenda, Kelly, and company were juniors again, while David and Scott had now become sophomores(*), and no one at any point acknowledged this weird rift in the space-time continuum.

(*) David would later take on an extra course-load so he could graduate with his friends, while Scott wouldn't live to see his junior year. By the time the second season began, Douglas Emerson had been dropped from the regular cast, since Scott was unnecessary once David had an in with the cool kids. But then the show wanted to do a sweeps stunt where they could promise the fans that somebody would die, and there was a series of print ads with a picture of the full cast - plus Emerson inserted randomly in the back - and the tagline, "Tonight, they lose one of their own." And, of course, people fell for it. A bunch of girls in my class were terrified that Donna or Kelly were going to get whacked.

As a continuity nerd, this always amused me. Years later, I was at a Writers Guild of America event where I bumped into a friend of a friend who was now a brand-new writer on latter-era "Beverly Hills 90210," and I joked to her and her fellow rookie that they should do a scene where Kelly is showing her high school yearbooks to one of the new characters and gets flustered when they ask why she and all her friends repeated their junior year. They were puzzled. I explained what happened back in the day. Their jaws dropped.

"That did not happen!" one of them insisted.

The other spotted a writer who had been on the show in those early years, flagged him down and asked him to confirm, which he sheepishly did.

"Look, we did what we had to do," he said, explaining that they all thought the show was doomed the second the characters went off to college (instead, the show ran seven more seasons after West Beverly, including a handful of post-college years) and so they wanted to stall as long as they possibly could. They didn't think most of their viewers would notice and/or care.

And that's the original "Beverly Hills 90210" in a nutshell, in a way. (Though, in fairness, more high-minded high school shows like "Friday Night Lights" have played similar games with their characters' ages, though never quite this blatantly.)

For those of you who watched the old show, got any particular favorite (or embarrassing memories) of it? "Donna Martin graduates"? "Squash it"? Dylan's wife blowing up getting killed? And how long, if at all, did you stick it out with "90210" 2.0?

Alan Sepinwall
Sr. Editor, What's Alan Watching

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Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "The Revolution Was Televised," about the last 15 years of TV drama, is for sale at Amazon. He can be reached at sepinwall@hitfix.com