Inventors and Inventions:
http://www.enchantedlearning.com/inventors/indexg.shtml
http://www.history.com/
http://inventors.about.com/od/astartinventions/a/FamousInvention.htm
http://www.edinformatics.com/inventions_inventors/
http://www.geniusstuff.com/blog/list/10-inventions-changed-world/