1 of 26
GLEEFUL INSPIRATION The pop star got the Glee treatment with the cast re-creating some of her most iconic videos and looks, as well as putting their own Glee-spin on songs like ''Toxic'' and ''Stronger.'' Spears herself made a few fleeting appearances, most amusingly trying to sell the idea of ranch dressing on pizza to the kids.
2 of 26
THRICE AS NICE Those who thought Spears' golden touch had tarnished were proven wrong when electro-pop smash ?3,? her ode to ménages à trois, became a near-instant number-one on the Billboard Hot 100 — her third ever, in fact (coincidence?). Even with its odd shout-out to folkies Peter Paul and Mary, the song and its attendant almost-too-hot-for-TV video put La Brit back on the map in a way that seemed to wipe fans' memories of her tabloid travails and lackluster VMAs performance right clean — at least for a good three and a half minutes.
3 of 26
CIRCUS SMASH Following her highly rated Britney: For the Record (either piercing docudrama or Circus infomercial, depending on how you saw it), a Good Morning America appearance and several other high-profile promotions, the album bowed even bigger than expected, not only bringing Britney her fifth no. 1 debut but — oops, she did it again! — making her the only act in Nielsen SoundScan history to have four albums move 500,000 copies or more in the first week, with 505,000 in sales.
4 of 26
NUDE ATTITUDE Rested and rejuvenated, Spears released the single ''Womanizer'' to advance her December 2008 album release, Circus, and was rewarded with record-breaking numbers, earning the biggest download numbers for a female since SoundScan began tracking digital music. She also showed off a new, more confident shape and attitude in the accompanying video, in which she played several different women too smart to be ''ized'' by a cheating boyfriend.
5 of 26
NEW LOVE...WITH A MOON MAN After her previous year's performance of ''Gimme More'' proved to be decidedly...less (as we'll see in an upcoming screen), La Brit returned triumphant to her old stomping grounds, opening the MTV VMAs broadcast with a sketch featuring Superbad's Jonah Hill. And she cleaned up nice with the moon men, too: Her Blackout album's autobiographical kiss-off ''Piece of Me'' earned the no-longer-falling star three awards — Best Female Video, Best Pop Video, and Video of the Year.
6 of 26
MOTHER OF THE YEAR After being hospitalized for a breakdown in January 2008, Britney recaptured some of her former sparkle in a well-received turn as sweet, slightly deranged receptionist Abby on the CBS comedy How I Met Your Mother. Her two appearances — once in March, and again in May — spiked the show's ratings big-time, and showed she was, to quote vintage Brit, ''stronger than yesterday.''
7 of 26
LAZY SUNDAY Less successful as a comeback vehicle was Britney's now-notorious 2007 VMAs performance of ''Gimme More.'' Although her appearance was touted as a showcase to mark her triumphant comeback, she seemed nervous, tentative, and lethargic, and the spectacle was lambasted by critics, a jumping off point for a succession of new personal lows and tabloid feeding frenzy.
8 of 26
BRITNEY SHEARS Earlier in 2007, amid reports that she'd been in and out of rehab, Spears shaved her head bald at a California hair salon, then got a couple new tattoos.
9 of 26
STRONGER? In November 2006, Britney filed for divorce from her husband of two years, Kevin Federline; the couple have two sons together, Sean Preston and Jayden James.
10 of 26
THE 'NIGHT' BEFORE Just a day before filing for divorce from Federline, Spears popped up on the Late Show With David Letterman wearing a form-flattering black dress and a chic new 'do.
11 of 26
BOOBS, SHE DID IT AGAIN A second-time-preggers Britney stole the thunder from the artist she was presenting at the 2006 Teen Choice Awards — her ''man'' Kevin Federline.
12 of 26
OH, BABY BABY Britney sports darker locks, a baby bump, and her son Sean Preston.
13 of 26
CANNY CAMERA Though they didn't last very long, Federline and Spears were smart enough to videotape their 2004 courtship, engagement, and wedding for Chaotic, their '05 reality series on UPN.
14 of 26
NOT A GIRL, NOT YET A MOTHER Spears announced she was pregnant for the first time in April '05. Sean Preston was her first and Federline's third; he has two kids with actress Shar Jackson.
15 of 26
HITCH ME, BABY, ONE MORE TIME The newlyweds celebrated their September 2004 nuptials by going clubbing in L.A. But the ceremony wasn't entirely official; only after a prenup was finalized did Britney file for a marriage license, three weeks after the wedding.
16 of 26
HE LIGHTS UP HER LIFE In June 2004, two months after Spears began dating 26-year-old backup dancer Federline, she popped the question. ''I kissed a bunch of frogs and finally found my prince,'' she said.
17 of 26
DROWN AND OUT Though Britney seemingly kills herself (or is murdered by the media, or something like that) in the murky video for ''Everytime,'' a ballad from 2003's In the Zone, she would only say the clip was about reincarnation.
18 of 26
WEDDING DAZE Britney's first marriage of 2004 began with her January trip to a Vegas wedding chapel with childhood friend Jason Alexander and ended with an annulment 55 hours later. ''That thing was a total ugh. I was not in love at all,'' she said later.
19 of 26
UNLIKE A VIRGIN In a perfectly engineered bit of pseudo-controversy, Britney sort-of stunned the world by smooching her mentor Madonna at the 2003 VMAs (she swears no tongues were, uh, wagging).
20 of 26
REBOUND HOUND After splitting with former beau Justin Timberlake, Britney was spotted getting cozy with other celebs, including Colin Farrell (pictured, in 2003) and Limp Bizkit singer Fred Durst.
21 of 26
SODA POP Britney briefly joined the sweater set for a 2002 Pepsi Super Bowl ad that placed her in various eras, from the '50s to the '90s.
22 of 26
VEXED IN THE CITY In her mediocre movie debut, 2001's Crossroads, Britney's character gets upset when her mother (played by Kim Cattrall) rejects her.
23 of 26
BLUE HEAVEN Before he got involved in that other wardrobe malfunction, Justin Timberlake and then-girlfriend Britney — drowning in denim at 2001's American Music Awards — were pop's royal couple.
24 of 26
HAT TRICK At the 2000 MTV Video Music Awards, Spears' medley performance of ''(I Can't Get No) Satisfaction'' and ''Oops!...I Did It Again'' prompted cohost Marlon Wayans to joke that she'd gone from the Mickey Mouse Club to the strip club.
25 of 26
SHIRTS AND SKIN A 16-year-old Britney instantly gained millions of teen (and dirty-old-man) fans with the naughty-schoolgirl video for her 1998 debut single ''...Baby One More Time.''
26 of 26
MOUSE OVER In 1992, Britney perfected her early dance moves in the All New Mickey Mouse Club, with costar Justin Timberlake (left).
Written by Leah Greenblatt, Tim Stack, Gary Susman, and Brian Hiatt