You can find the all the details here, but it's pretty much just what it says on the tin: read one YA book from each decade, beginning with the 1930s (admittedly, YA as we know it didn't really take off until the 1960s, but there were precursors). Anyway, after deliberating for far longer than was probably strictly necessary, this is the reading list I came up with:
1930s and earlier: Ballet Shoes by Noel Streatfield (1936)
1940s: Seventeenth Summer by Maureen Daly (1942)
1950s: The Witch of Blackbird Pond by Elizabeth George Speare (1958)
1960s: Camilla by Madeleine L’Engle (1965)
1970s: M.C. Higgins, the Great by Virginia Hamilton (1975)
1980s: Interstellar Pig by William Sleator (1984)
1990s: The Ear, the Eye, and the Arm by Nancy Farmer (1994)
2000s: I Am the Messenger by Markus Zusak (2002 in Australia; 2005 in U.S.)
The rules state that re-reads are acceptable, but all of these will be new to me. I plan on reading them in order, so expect a review of Ballet Shoes in this space in the near future.
Happy reading, everyone!