How they managed to keep this quiet is a shocker itself, but NBC execs will announce today at their annual upfront presentation in New York that they've been developing "Heroes: Origins," a spin-off series of this season's breakout hit that will, at least temporarily, replace "Heroes" on NBC's Monday night schedule.

The new show has been ordered for six episodes, and will introduce a completely new set of characters. The coolest part: In an effort to make the show interactive (and, I'm guessing, to squash what is going to be some griping by "Heroes" fans who are unhappy that the original show won't return in September), NBC will ask fans to vote on which is the new characters is their favorite, and that character will then become a regular cast member on the original series.

Among the other highlights of NBC's fall 2007 schedule:

- "Scrubs" is back for one more year, but with a shortened 18 episode-season.

- All three "Law & Order" series are back.

- "Friday Night Lights" will now air on Friday nights, finally.

- NBC has ordered 30 episodes of "The Office," including five one-hour eps, and 25 installments of "My Name Is Earl," as opposed to the usual 22-24.

- A new reality series called "World Moves," is a dance talent competition, created by "American Idol" judge Randy Jackson.

- And the new "Bionic Woman" is the big Wednesday night debut for NBC next season.

Check out what is believed to be the complete NBC line-up here, though all the networks continue to tinker with their line-ups right up 'til their upfront presentations to advertisers and the media.

I'll be heading over to Radio City this afternoon, so I'll update later with fresh info and some feedback on which new shows look promising.

- posted by Kim