This is a great project for adults, but also fun for pre-teens, teens and even children if you pre-sew their books or even prepare smaller booklets. I do this with smaller ads sometimes stapling two or three together then ripping out the staples and sewing in the holes to make a small booklet for my little one's to decorate. They can use them for glue books or gesso them.
Here is a video of my Recycled Junk Mail Journal:
Oh . . . before I forget, I have to share a funny story about gesso. My daughter saw a semi on the road the other day and told her brother that she thought it was a Toys 'R Us truck.
"How can you tell? It doesn't say anything?" he noted.
"I know, I think they got smart and covered it in gesso so the bad guys wouldn't steal toys from the truck." :)
That goes to show you that if you use gesso enough your kids will think all things white are covered in it. I can't wait until winter.