I would like to recommend a website called DLTK's Crafts for Kids - http://www.dltk-kids.com/ - They are very creative and have brilliant ideas to create crafts using a toilet paper roll. The templates are printable, or you can sketch it, like me, which provides another opportunity to your children to draw, and practicing colouring pictures. Every time I teach a new letter to my son we create something out of a toilet paper roll.
The picture below shows some of the crafts we have done using DLTK's ideas: goat, queen, octopus, elephant, fireman, lion, karate kid, kangaroo and pig.
We also have created a pirate and monkey out of a paper plate, and a giraffe out of a paper bag.