Here's the info I extracted from a post by dfourer earlier this spring. I will contact David directly, but I wanted to check if anyone else knew anything and/or if any Chicago folks were planning to attend?

Thanks,

Kristen

[snip]
RE: Urban Chicago
Posted by: dfourer z5 Chicago (My Page) on Sun, Jan 30, 05 at 21:20

Rogers Park Spring Plant Swap !!!

I finally got the information.

It's informally held every year on the first Saturday in June, at Sullivan High School Parking lot, 6631 N Bosworth Ave, Chicago, IL (not affiliated with the school)
Starting about 9:00 a.m. - You don't want to be late, because the plants get swapped amazingly fast, and then there is nothing left.

You can contact my friend Karl and tell him you expect to go. He may be able to update us by e-mail when it gets close. In accordance with GardenWeb instructions, I'm going to forward your e-mails to Karl to prevent him from getting spam.
You can also contact me a few weeks in advance and I will verify the time and date. My e-mail I'm willing to post: dfourer**A:T**comcast.net

Here's how it works: save some cheep nursery pots or boxes or whatever, dig up your over-crowded or unwanted plants the night before and load in the car, drive to the school parking lot Saturday morning (on time).

Hope to see some of you there,
David Fourer
[/snip]

"The plant swap is Saturday, April 30th this year. Thats this Saturday.
At Sullivan High School Parking lot,
6631 N Bosworth Ave, Chicago, IL (not affiliated with the school)
Starting 10:00 a.m. I'm told.
You don't want to be late, because the plants get swapped amazingly fast, and then there is nothing left.
My phone is 773-465-9329
-----David"