Doors Open 2012 -- What Are You Checking Out?

This weekend is Doors Open Toronto!
“More than 135 architecturally, historically, culturally and socially significant buildings will open their doors for the weekend and highlight the people who built our city. All for free!” 
I haven’t figured out yet what I want to see. There are a lot of places to consider:

Thus far I’m contemplating the R.C. Harris Water Treatment Plant, and Native Child and Family Services of Toronto on College. I’m disappointed that the Don Jail isn’t on the list this year. I might pop by Fort York if I can’t settle on anything...

Any suggestions on venues worth attending? Let me know in the comments.

See also
Toronto Star Doors Open Listing
BlogTO Doors Open Guide