clever (and cheap) build for 3rd hand supports

The author built these to originally help hold up cabinets, but I can see lots of uses for them.  He drilled holes in the curtain rod to make it extendable (and lock into place with a key).  Then put a foot on the bottom for fine adjustments.

http://www.homemadetools.net/forum/ikea-curtain-rod-third-hand-supports-64550?homelistings#post101863