If you've ever worked on a project where you needed another person to hold something against a ceiling while you screw it in, and that person is not going to be available when you have time to do the job, you can make a "3rd hand" out of two (2) 2x4's, some scrap 3/4" pine, two (2) four inch long x 5/16" carriage bolts, four (4) washers, and two star knobs available from Rockler.com (part # 23812).
For less than $10.00, you can put the whole thing together in about 30 minutes.
I made it at TechShop! I have a router table / saw at my house, but my shop is cramped and it's tough to deal with 8' 2x4s. Doing it at TechShop made it a breeze to put this together!
Step 1: Route two 3/4" slots in two (2) 2x4s
Using a 3/4" router bit, adjust it so that it cuts a "dado" type slot about 3/4" into a 2x4. Use the fence on a router table to adjust the location of the cut so that the slot is straight.
Cut one of the 2x4s to a length of 3 feet.
Route two slots along the entire length of the 3' 2x4.
On the other 2x4, route two slots about 3 feet from the end.