There's a growing market for reclaimed/salvaged building materials.
Check out Planet Reuse or http://www.build.recycle.net/ , or there are probably similar local organizations in your area.
I believe Habitat for Humanity tries to use reclaimed material as well; you might look into donating yours.
If you're talking DIY projects, I'd say your imagination is the only limit there!
It's a little hard to say more without knowing more specifics about what kind of materials and project.
(As a start, I've seen some pretty neat projects using old trim to make picture/mirror frames, or shelves.)
sustainability.stackexchange.com/users/57/Yumecosmos
Obviously, the most effective way to avoid generating a lot of waste is not to do the remodeling project, or to do only a small part of it that gets you the most value.
Construction generates a lot of waste !
Drywall & plaster can be broken up and used as a soil amendment.
The older trim and lumber , the better that wood will be.
If you have any old growth, wood, you could reuse it in your project.
You might even look at exposing the wood as part of the beauty of the new room.
Old carpet can be hard to reuse.
It's usually pretty nasty.
Google had a few suggestions, like insulating your compost pile.
Carpet is also hard to recycle, but your municipality may have a carpet recycling option.
sustainability.stackexchange.com/users/27/Jay Bazuzi
If you are in a large city, drywall can be recycled into drywall.
Check with your local agency.
The grey stuff in drywall is mostly gypsum -- Calcium magnesium sulfate.
Yes it can be used as a soil amendment if you have neutral or acidic soils.
Read up before you do it.
It rototils reasonably easily.
Wood: See above. Carpet.
Works great upside down as weed barrier cloth.
Cut in widths to fit the aisles in your garden, use around trees.
Decorate with wood chips if you want.
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You could try to pass on whatever you don't want to other people, free-of-charge, via the Freecycle Network .
The Wikipedia article provides an overview of that organization.
sustainability.stackexchange.com/users/450/Ciaran McHale
Junk to useful: Plastic barrels: Take a vertical slice off of one side, leaving an opening about 16" Adjust as needed.
Good bad weather generator cover.
Would also make a good barbecue cover.
Plastic pails:
I scrounge them by the thousand, wash them
put 12 1" holes in the sides as use them for nursery pots.
Carpet:
Lay upside down in the garden for mud free paths.
Roll up and store dry overwinter will double their life.
Wood scraps:
We have a company in industrial centre that collects all the 2x4 and 2x6 off cuts from several truss companies, a millwork company, and three mobile home/camp unit makers.
They chip and shred them and sell it as horse bedding.
Pallets:
Lean against each other in pairs, and tie one edge with baling twine.
Instant snow fence.
Assemble 9 as and extended E or 8 in a swastica
and you have a 4 bin composter.
Sawdust, wood chips.
Wood pellet heating.
sustainability.stackexchange.com/users/400/Sherwood Botsford
I am remodeling a room in my house and have a bunch of material that may end up in the garbage.  I would be throwing away carpet, plaster and planks, trim and etc.  I would like to not throw this stuff away if there is any clever/ helpful use for it.    Does anyone have any ideas on if I can reuse this stuff in/on any other project/activities?
What reuses are there for surplus building materials?
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<reuse><building-materials>
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sustainability.stackexchange.com/users/91/Linger
There's a growing market for reclaimed/salvaged building materials. Surplus materials can also be passed on through the Freecycle network. One way to avoid generating a lot of waste is to simply do the most important part of a remodelling project. There is a growing market for building materials, which can be recycled or re-used via Freecycle schemes. Waste can be minimised by limiting building projects to the essential.
There is a growing market for building materials, you can also Freecycle them. Materials such as drywall can be recycled. You can avoid generating waste by minimising building projects to the essential.