The South Park Blocks are a series of small, one block square blocks running down the south of downtown Portland, OR from Salmon St to I-405. They lie between Park and Ninth avenues.
The park blocks themselves are green, level pleasant squares that have some good tall trees that provide good green shade in the middle of downtown. The north area of the park holds a brick yard that sometimes holds Portland's farmers market. The park also has has some nice large copper statues of Abraham Lincoln and Teddy Roosevelt.
However, as with the mall in Washington, DC, the main point of the park blocks is not what is in them, but what is around them, which includes such institutions as the Portland Art Museum, Tyger's Heart Theatre, the Arlene Schnitzer Concert Hall, and, of course, the Safeway of the Damned.
After crossing Market Street, Park Avenue turns into a wide sidewalk and the park blocks run through the Portland State University campus, becoming their quad, as it were. At this location, they have the newly built trolley tracks running through them.
Also, for visitors of Portland, eating your lunch on the south park blocks may be less nerverending then doing so on the North Park blocks.