"ER's" Live Episode
Back when "ER" was a powerhouse prime-time drama (remember those days?), NBC tried a daring experiment to kick off the show's fourth season: They filmed the premier episode live. And not just live, but twice live -- one for the East Coast, a second for the West. More suspenseful than the plot was the fear that they might mess up -- a camera might shut off, lights might go out or an actor might forget lines (after all, the episode required 30 separate rooms, 20 speaking parts and about 40 extras). As insurance, the studio hired extras to play out "spare" scenes, so if anything went wrong, they could cut away and not lose momentum. This insurance was never claimed, and the live "ER" episodes are considered a great triumph in TV history. There's only one debate still raging: Which version was better, East Coast or West Coast?

"24"
The punishing white time code, set against a stark black screen, that gradually ticks toward the 24-hour mark -- it's become one of the most suspenseful icons in TV history -- and each season, another doomed day dawns for "24" fans. What began as a simple gimmick (to create a single, hyperactive day in the lives of the fictional Counter Terrorism Unit) now dictates our Monday nights for five nerve-wracking months. The intricate spy-versus-spy plotting is always punctuated just before a commercial break, and every hour concludes with a seizure-inducing cliff-hanger. There's only one thing more non-stop than the thrills, and that's that damnable clock.

"The Real World"
What would life be like without the "original" reality TV show? Whose idea was it to take a dozen bitchy, attractive rich kids and stick them in a house together? "The Real World" not only entertained audiences with quotidian arguments about who should do the dishes and who sucked face with whom; it also launched a thousand spin-offs, from "The Surreal Life" (even more annoying people with even less to do) to "Drawn Together" (the vicious animated parody). Our favorite: "Average Joe," which featured a bunch of actors pretending to be high-strung contestants and one ordinary guy from Pittsburgh who wasn't privy to the joke. When it comes to gimmicks, you can't beat reality TV -- the genre that demands you turn on the tube to see the real world.

"Cop Rock"
Nothing could have prepared America for a kick-line of state troopers linking arms over shoulders and parading through crime-addled streets with street-smart razzle-dazzle. No series in history ever combined the cop drama with the Broadway musical so beautifully -- or even tried. Critics tuned in because it was created by Steven Bochco (the brains behind "Hill Street Blues"), but they were horrified to discover Gospel-singing juries and punny episode names like "No Noose is Good Noose." While musical theater has been a recurring TV gimmick, "Cop Rock" was widely regarded as the worst television show of all time, and, after 11 episodes, it brought new meaning to the term "show-stopper."