Here is my son's lapbook that we made along with the Human Body Unit we did last week. He loves to see these as finished products and says this is the best one so far (it is our 3rd). We did all these random books last week and then his favorite part today and yesterday- assembly and decoration.
I also let me 4 yr old make one....but his are simple books with no writing, more coloring, cutting and glue. But he likes to feel involved even though he doesn't quite have the attention span or writing skills for the more involved ones.