In the past, standalone gay-themed episodes of network TV shows were formulaic and rife with stereotypes, but lately they have been at the forefront of positive lesbian portrayals, proving that understanding and acceptance of lesbians and bisexual women is evolving and improving.

Lesbians get blamed for many things, from the destruction of the nuclear family to the death of traditional values, but no one can deny lesbians are good for one thing, at least: boosting TV ratings during the critical "sweeps" periods of the year (November, February and May), when audience size is measured and later used to set advertising rates.

Ever since bisexual British lawyer, C.J. Lamb, pulled poor, meek little Abby Perkins into a tepid smooch on L.A. Law, the lesbian sweeps moment has been a staple of the television year. And no, the huge, wealthy, lesbian demographic isn't the intended audience of this Sapphic largesse. It's designed to appeal to a somewhat different audience (perhaps you can guess who). Still, many of the most famous, and infamous, lesbian television moments have taken place during sweeps periods.

Sometimes lesbians actually become genuine and essential parts of the ensembles of television shows, and aren't just used as ratings-boosters. Joss Whedon managed it with Willow and Tara on Buffy the Vampire Slayer, and South of Nowhere is doing it now with Spencer and Ashley. Still, most sweeps period TV lesbianism is used primarily for its sensationalism and power to increase audience share.

Among all the silly, titillating, unrealistic, contrived and often downright offensive lesbian sweeps moments, are there any that might appeal to actual lesbians? Somewhat surprisingly, yes. Here are 10 great (or at least, important) lesbian moments in sweeps history:

10. Jadzia and Lenara on Deep Space Nine — It actually aired the night before fall sweeps began in 1995, and was about two heterosexual lovers, one of whom was newly living in the body of a female host (yes, it's science fiction), but the kiss between Jadzia Dax and Lenara Kahn on Star Trek: Deep Space Nine was one of the most romantic same-sex kisses ever shown on television.

For those who stopped watching Trek somewhere around the time Capt. Kirk and Lt. Uhura shared the first interracial TV kiss, Dax and Kahn are members of a species known as the Trill, where different individuals serve as hosts for symbiotes. There is a whole set of social and cultural rules about how symbiotes in new hosts are supposed to interact with those they knew when in their former hosts, and none of them involve passionate kissing. Still, no one got too upset over Jadzia and Lenara's lip-lock, and even though the Star Trek universe is pretty much resolutely heterosexual, we'll call this a great lesbian moment in sweeps history — or at least, a very pretty one.

Deep Space Nine's only other foray into lesbianism wasn't so positive; in a recurring world called the Mirror Universe, the evil versions of regular characters Kira Nerys and Ezri Dax demonstrated their dark side with lesbian attraction. Yawn.

9. Jennifer Aniston and Winona Rider on Friends — May 2001 sweeps brought us the much-hyped kiss between Friends regular Rachel (Jennifer Aniston) and her lesbian friend Melissa, played by guest star Winona Rider. It was heavily featured in promos for the episode leading up to the sweeps period, and the kiss itself was, basically, not much. The plot twist was that Rachel had actually kissed Melissa back in college, and Melissa either didn't remember it or was pretending not to, which goaded Rachel into kissing her again, at which point Melissa went and rented a U-Haul, which is either extremely offensive or tragically accurate, depending on who wants to know.

But a non-sweeps moment on Friends actually holds highest pro-lesbian honors. In January 1996, Ross' former wife, Carol (Jane Sibbett), married her lover, Susan (Jessica Hecht). Ross wasn't totally thrilled with this development, but when Carol's parents declined to attend the wedding, Ross stood in for the father of the bride and walked Carol down the aisle. (The fact that the brides don't kiss does take some of the shine off the moment.)

7. C.J. and Abby on L.A. Law — Feb. 7, 1991, wasn't exactly a great date in lesbian television history, but it was an important one. The kiss between C.J. Lamb (Amanda Donohoe) and Abby Perkins (Michele Green) on L.A. Law was, at best, boring, but it was the first time a television show had deliberately used a lesbian kiss to boost ratings during sweeps week — and it is supposedly the first same-sex kiss in the history of television.

6. Marge Simpson's Sister and the Fake Lesbian on The Simpsons — There must have been something particularly Sapphic in the stars on Feb. 20, 2004. That sweeps night marked the debut of Showtime's lesbian drama, The L Word, and was also the night that Marge Simpson's sister came out as a lesbian on The Simpsons, and engaged in an apparent same-sex kiss. (Of course, the object of her affection turned out to be a man pretending to be a woman, so it didn't count, if animated characters count in the first place.)

5. Roseanne Barr and Mariel Hemingway on Roseanne — Some lesbians weren't wild about the Roseanne Barr and Mariel Hemingway kiss on the sitcom Roseanne in 1994. In fact, the best part of that episode was probably the final scene, where Roseanne's husband, Dan, pretends to sympathize with her over the indignity of being kissed by a woman at a lesbian club, while obviously finding it a big turn-on. Roseanne killed the moment by recounting a story about watching two guys making out on the dance floor. Still, Roseanne went to the wall with the network to keep the kiss in the episode, and consistently included gay characters on the show.

The scene where a very pregnant Jackie, left at the bar while Roseanne dances with Mariel, chases women off when they hit on her by invoking the rage of her butch girlfriend, Roseanne, didn't hurt, either.

4. Marissa and Alex on The O.C. — The Marissa (Mischa Barton) and Alex (Olivia Wilde) relationship on The O.C. had a lot of problems. The women were, like everyone else on the show, unrealistically and plastically perfect. The relationship bombed out in a completely out-of-character way, leaving viewers going, "Huh?" But the early days of their affair were really sweet, and their first kiss, despite its Playboy Channel aesthetic, was hot. Not coincidentally, it took place during sweeps, where it sent the show's ratings soaring.

3. Xena and Gabrielle on Xena: Warrior Princess — During February 1999 sweeps, Xena and Gabrielle took a bath together.

Okay, Xena and Gabrielle took lots of baths together. This particular episode, "Paradise Lost," was singled out by GistTV.com as a sweeps month lesbian moment way back in 1999, when they wrote, "[T]here's a scene where Xena and Gabrielle bathe together, and Xena gets up naked (discreetly), and another scene where Xena gives Gab a massage and … well, it all sounds less like Alice in Wonderland than the Playboy Channel. Must be Sweeps month."

2. Dr. Kerry Weaver and Dr. Kim Legaspi on ER — The November 2000 sweeps were livened considerably by the coming-out of ER's Dr. Kerry Weaver (Laura Innes). Dr. Weaver was a longtime regular character who fell in love with a woman, a beautiful psychiatrist, Dr. Kim Legaspi (Lost's Elizabeth Mitchell).

While her first kiss with Kim was a sweeps ratings booster, Kerry actually remained a lesbian even after sweeps were over, and loved and lost Kim to her own fear of coming out. Unfortunately, she then loved and lost hot butch firefighter Sandy Lopez (Lisa Vidal), too, and got embroiled in the obligatory lesbian mommy story line followed by a custody battle with Sandy's parents over her and Sandy's son after Sandy died.

All of this can really make a girl miss Dr. Maggie Doyle (Jorja Fox), ER's original dyke, a cop's daughter and vegetarian who took her dates to the shooting range, but never had any hot sweeps month lesbian kisses.

1. Ellen DeGeneres and "The Puppy Episode" — It's been analyzed and recapped and critiqued to death, but the famous "Puppy Episode" of Ellen wasn't just the biggest lesbian sweeps moment. It was the biggest lesbian moment in television history. Airing on April 30, 1997, it featured a galaxy of lesbian and lesbian-friendly guest stars including K.D. Lang, Melissa Etheridge, Laura Dern, and Oprah Winfrey as Ellen's shrink. The show didn't survive another year, and there's been no huge surge of queer shows in its wake, but it changed the face of television forever.