- January 4: Ashlee performs "La La" at the Orange Bowl halftime show; at the end of the performance booing is heard from some of the spectators.
- January 6: The "Pieces of Me" single is certified platinum by the RIAA.
- January 7: Top of the Pops performance of "La La" airs. (U.K.)
- January 8: CD:UK performance of "La La" airs. (U.K.)
- January 12: After an interview, Simpson performs the song on Today with Des and Mel. (U.K.)
- January 15: Top of the Pops Saturday performance of "La La" airs. (U.K.)
- January 16: Popworld performance of "La La" airs. (U.K.)
- January 24: "La La" CD single released in the U.K.
- January 26: The second season of The Ashlee Simpson Show begins airing in the U.S.
- February 7: Simpson appears on TRL to talk about her upcoming tour, as well as other things.
- February 10: The second season of The Ashlee Simpson Show debuts on MTV Canada.
- February 16: Tour begins in Anaheim, California.
- February 18: Second date of tour in Universal City, California.
- March 29: "La La" is certified gold by the RIAA.
- March 30: Last (tenth) episode of the second season of The Ashlee Simpson Show airs in the U.S.
- April 20: Tour ends in Grand Prairie, Texas.
- April 24: Ashlee is shown having a trick played on her in an episode of MTV's Punk'd.
- May 3: Ashlee shows off a new hairstyle—shorter, with a reddish-blonde color—at a Candie's event.
- June 19: Ashlee performs "La La" at the MuchMusic Video Awards, and also shows off another new hairstyle, this time fully blonde and longer than her previous style.
- August 26: The movie Undiscovered is released.
- August 31: Ashlee begins shooting her "Boyfriend" video (shoot continues on September 1).
- September 6: "Boyfriend" officially hits radio.
- September 12: "Boyfriend" video debuts on Making the Video.
- September 13: Ashlee appears on TRL for the premiere of "Boyfriend".
- September 14: "Boyfriend" debuts on TRL countdown at #9 (moves up in the following days)
- September 21: Ashlee begins a short tour with a show in Portland, Oregon.
- October 3: Simpson celebrates her 21st birthday in Las Vegas. She also performs. A show about her birthday, Ashlee Simpson Live and Legal, airs on MTV later in the month.
- October 8-9: Simpson appears on Saturday Night Live for a second time, this time successfully. She sings "Catch Me When I Fall" and "Boyfriend".
- October 18: U.S. release date of Ashlee's second album, I Am Me.
- November 1: Simpson appears on MuchMusic's MuchOnDemand in Canada.
- December 15: I Am Me certified platinum by the RIAA.
- Mid-December: Simpson collapses due to exhaustion after performing in Japan and is briefly hospitalized. Afterwards, she takes some time off to rest.
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