Check out these 3 great sites:

 The Freecycle Network - www.freecycle.org
The Freecycle Network is a project of RISE, Inc., a 501(c)3 nonprofit organization whose mission includes reducing waste, generating employment training and fostering cooperation between other nonprofit organizations and the public.  It's a grassroots movement of people who are giving (& getting) stuff for free in their own towns.  Freecycle provides individuals and non-profits an electronic forum to "recycle" unwanted items.  One person's trash can truly be another's treasure!

Arts & Scraps - www.artsandscraps.org
16135 Harper, Detroit, MI 48224   (313/640-4411)
Mission Statement: To provide children with affordable and creative experiences using recycled industrial scraps to actively involve them in learning, increase their confidence and encourage independent thinking.
Take the I-94 Cadieux exit, #223.  Turn south towards the lake.  Immediately turn right on Harper (the first intersection) - go 3/4 mile.  Located on the right, behind a wrought iron fence and parking lot. 
Look for the glass globe lights on the gate and signs on the building.
Public hours - Tuesday - 11-6, Thursday - 11-6, Saturday 11-4