Bending wood with ammonia is not really DIY, but I show the process, which is extremely effective. There is also a commercial product that is pre-treated flexible wood, which hardens after being clamped in the desired shape.
http://boingboing.net/2011/05/06/inventables.html
Hmm, it seems the product may no longer be available -- I can't find it at Inventables.
https://www.inventables.com
Pre-treated flexible wood product patent:
https://www.google.com/patents/US5360631