The Fonz is gray, the Nanny's married and for some reason, we still care.

Banking on the power of nostalgia, networks are digging deep into their vaults to produce TV-show reunions.

In recent months, "The Nanny Reunion: A Nosh to Remember," (search) "The Dallas Reunion: Return to Southfork" (search), "The Seinfeld Story" (search) and "Happy Days: 30th Anniversary Reunion" (search) have hit the airwaves, and the "One Day at a Time" reunion is set for this Tuesday.

But do these shows fill a void for viewers whose favorite shows have gone off the air, or are they just a cheap and effective way for networks to cash in on an old program?

Judging by the favorable ratings, it seems the specials fulfill a need on both ends.

"These are mostly over-the-hill actors who are not going to ask for a lot of money. All you need is a theater and a live audience, which is free. From a network perspective, it makes a lot of sense," New York Post TV writer Don Kaplan told FOXNews.com.

Curiosity over how well or not so well once-beautiful stars have aged is one of the chief reasons specials such as "The Dallas Reunion" and "The Nanny Reunion" received 9 million and 3.6 million viewers, respectively.

“I loved 'Growing Pains' when I was younger," said 25-year-old New Yorker Allie Shenker, who tuned in last year to watch "Growing Pains: Return of the Seavers," a "reunion" movie that caught up with the Seaver family. "I watched the reunion because I wanted to see how the cast looked, and I was hoping that Leonardo DiCaprio would make an appearance."

However, nostalgia, not schadenfreude, appears to be the driving force behind viewership — the fact that fans once again get to spend time with people who used to fill their evenings with laughter and excitement.

“['Beverly Hills, 90210'] was my favorite show of all time,” said Mandy Porter, a 27-year-old graduate student from California, who watched 2003's "Beverly Hills 90210: 10-Year High School Reunion," but was slightly unimpressed.

“It glossed over all the drama. Like, if ['90210'] was going to have a reunion show, I think they should have had Jennie Garth and Shannen Doherty talk about how much they hated each other and not have had them holding hands.”

Anna Hoffman, a 61-year-old pre-school teacher from New York, tuned in to the "The Seinfeld Story," a reunion show that aired in November, mainly to reconnect with the characters she's been missing.

"It was nostalgic. I probably wanted to hold on to seeing them. I guess I also needed some closure," she said.

But she also revealed another popular reason for watching reunion shows — to see how the actors relate to each other as people, out of costume.

"I wanted to see how off-the-cuff they interacted with one another. I wanted the inside scoop," she said.

If reunion specials, which tend to be predictable, cheesy and heavy on the blooper reels, don't inspire you to program your TiVo, there are plenty of other options for those missing yesteryear.

For instance, ABC is planning to bring back the 1970s show "Little House on the Prairie" as a short-form series.

And the television show is one of the fastest growing DVD genres, indicating that where there's an old show, there's an audience willing to watch.

“The thing about really good television is that people form an emotional bond with it. … A lot of these shows have a built-in audience and people will seek them out,” said Brian Lucas, a representative for Best Buy, the first chain store to devote an entire DVD section to television shows.

“People like to relive shows like 'Cheers' and 'Taxi.' There's a reason why we carry them,” he added.

In fact, Universal Pictures alone has seen a 400 percent increase in sales, thanks to the release of "The Munsters" and "Miami Vice" DVDs.

Some, however, feel the reunion show trend is fueled not so much by a longing for old shows, but by a lack of quality television.

“Shows like 'Family Ties,' 'Growing Pains' and 'The Cosby Show' had better family values than the shows that are on now. I think those shows provided a good model, albeit mostly unrealistic, on how families should communicate with each other,” said Porter, who is saving up for "The Honeymooners" DVD.

But visiting the past via a reunion show is not a new phenomenon. In fact, many networks have checked in with old favorites on more than one occasion.

CBS has reunited "The Carol Burnett Show" cast multiple times over the years, and all of the shows drew large audiences.

Similarly, the "Happy Days" reunion was the second of its kind, the first taking place in the early '90s. The "Growing Pains" reunion movie was also not a first — "The Growing Pains Movie" aired in 2000 and attracted 15 million viewers.

But when it comes to milking an old show, "The Brady Bunch" is the cream of the crop. "The Brady Bunch 35th Anniversary Reunion: Still Brady After All These Years," "A Very Brady Christmas," "The Brady Girls Get Married" movie and its short-lived spin-off show, "The Brady Brides," have all aired since the original show got cancelled.

So much Jan and Marcia, however, was not enough to satisfy Wisconsin native Leah Goldfarb, 33.

"I watched the 'Brady Bunch' reunions mostly for nostalgic reasons. They fell a little short, because you can't duplicate the feelings you had when you first watched the show," she said.

Indeed, like real-life reunions, specials that get old casts together again can sometimes be depressing, harkening back as they do to time gone by.

"I feel sad when a show is canceled. Why do all the good shows have to end?" Hoffman said.