see below for high resolution scans of photos I own 

Danica's monthly TV schedule (US only)

• She does not appear in episodes 12-16, 20+21, 25-27, 35, 38, 41, 44, 49, 52, 55, 59-65, 67, 70, 72-77, 79-84, 88-91, 95, 111, 113. Her appearance dropped very much in the forth and fifth season. The reason was that Danica wanted to have more money (by Time Warner via Dennis Barron):

First season	100%	only 6 episodes
Second season	57%
Third season	73%
Forth season	50%
Fifth season	26%	minor appearance in ep. 87 and 92
Sixth season	86%

• Also she is nearly always called "Winnie", her actual name is Gwendolyn.  Quote from episode 1:

WINNIE: Gwendolyn. I don't want to be called Winnie anymore, my real name is Gwendolyn. 
• Young Winnie is played by Jenny Drugan 22.

• Mr. Cooper, Winnie's father (played by H. Richard Greene) 23, 28, 40, 46, 66
• Mrs. Cooper , Winnie's (played by Lynn Milgrim) 23, 28, 46, 66
• Winnie's older brother, Brian, (played by Bentley Mitchum) was killed in Vietnam (see episode 1), buried in episode 2 and shown in a flashback in episode 23.

Trivia:

• Danica means "the Danish" in Latin and "morning star" in some Slavic languages. Her parents picked her name out of a book for baby names (according to her on Celebrity Sightings (link defunct) Chat, 18 June 1998). 
• Danica took dancing lessons together with her sister crystal even before she moved to Los Angeles with her mother in 1982, see article.
• At age 9 Danica did her first commercial. At age 11, she did a Mountain Dew commercial. In 1986 she appeared in a Volkswagen commercial.
• At age 10 she appeared in two episodes of the TV series The Twilight Zone.
• The first kiss in her life was with Fred Savage on "The Wonder Years" pilot, when she was 12.  See interview with Danica. 
• Danica was nominated for Best Young Actress Starring in a Television Series for the 11th Annual Youth in Film Awards 1988-1989 for her role in "The Wonder Years." 
• Danica and her sister Crystal were students of Diane Hill Hardin's Young Actors Space (like Leonardo Di Caprio).
• On December 23, 1989, Danica appeared alongside Josh Saviano, Nicole Eggert and Jeremy Miller as a guest on "Wide World Of Kids." 
• There are reports that Danica was an extra in the movie "The Nutty Professor" with Eddie Murphy. She was the girl dressed in a blue jean outfit in the halls of the college eddie murphy's character teached in. (she walks by real quick).  She is not listed in the titles, so can anybody confirm this?
• In March 1998 Danica and Fred Savage appeared together in an episode of "Working," a show in which he plays the regular character Matt. There were some funny lines recalling "The Wonder Years" like when co-workers as him if he plans to see her anymore.  MATT:" I don't even like her! She reminds me of a girl I knew growing up." (Audience truly laughs). See transcript, anouncement of NBC and article from TV Guide about this episode of "Working." Jason Hervey was also a guest star in this TV series but in a different episode.
• On May 4, 1998, Danica appeared on a one-hour episode of the new LOVE BOAT: The next wave series.  The same day she was interviewed on a segment of "American Journal". 
• It was in a third-year abstract algebra class that she met her boyfriend Jason Richard, now 25 (1998) and a computer software product manager. 
• Danica McKellar can be seen in the Debbie Gibson video "No More Rhyme" which was released in mid-1989. It can be found on the A*Vision video release "Live Around The World".
• Danica McKellar is NOT in the Paula Abdul video "Forever Your Girl". I have looked closely at every frame on a PAL high-resolution screen. The young dancing girl with the electric guitar looks a bit like her. But the shape of their faces are different when I compare with Danica in 1989, the production year of that video. Danica McKellar is also not mentioned in the end titles.
• Danica likes to ski and has participated in several charitable ski tournaments. 
• Danica supports the organization Earthtrust.
• There is a rock band called "Winnie". Bass player/drummer Jason had a crush on a girl at his school who looked like Winnie Cooper. He would always refer to this girl as "Winnie," and one day he suggested that the band be called Winnie. Visit their homepage.
• Danica appeared on "Home & Family" on March 17, 1998 and on "Eyewitness News" on May 6, 1998.
• On January 30, 1999, Danica had her musical debut as Rizzo in GREASE. This happens at The Grove Theater in Upland, which is half hour east of downtown LA.  The show ran on weekends until Feb.28th.
• Danica will star in a movie that is filmed at the moment in Georgia, USA, by Channel 12 Productions in Winder, GA. The movie is titled "Good Neighbor" and is a thriller or murder mystery. Look for it out in video stores near you in six months or so. (August 2000)
• Danica is very actively supporting math teaching in schools.  
• Danica gives online advice about math problems, see her website.
• On Thursday, July 13, 2000, Danica gave a personal testimony at a hearing of the California Committee on Science, Subcommittee on Technology to discuss a Review of the Morella Commission Report: Recommendations to Attract More Women and Minorities into Science, Engineering, and Technology. 
• She talked to an audience of math teachers on April 12, 2000, Chicago, at the press conference announcing the release of "Principles and Standards for School Mathematics". 

• Danica has written, directed and played in a new short film, "speechless..." She won as Best First Time Director Short Films at the Hollywood Underground Film Festival 2002.
• Danica is starring as the young mathematician Catherine in the Tony and Pulitzer Prize winning play
  "Proof" at the San Diego Repertory Theater. The show runs Sep 27 to Oct.26, Tue-Sun nights and Sunday matinees.
• There is a new Official Danica McKellar website.
• On July 19, 2005, a full article appeared on her in The New York Times and on November 18, 2005, another full article in The Los Angeles Times.
• Danica worked as a writer, director and producer of the short movie Broken.
• Danica appeared on the Food Network as part of their new show "Celebrity Diet Secrets" on January 1st, 2006, at 9pm and 11pm, January 7th at 4pm, and January 8th at 5pm. She'll talk about her healthy eating habits and how yoga keeps her in shape.
• In 2007 Danica wrote a book with the title "Math doesn't suck",which ranked 6th in the LA Times bestseller list and 4th in the Amazon bestseller list in September. In December Amazon put it in the list of the Best Book of 2007. There is also her website Math doesn't suck.