Create three charts: A thing, a place, and a person. In small group we discussed the difference between a common noun and a proper noun. The fourth graders then had to brainstorm example of each. They had a lot of fun and did not realize that they were learning to identify proper and common nouns.
While I was working on this post I remembered some great resources that other teachers have shared.
Check out Crazy For First Grade's free noun sort.
Or Step Into 2nd Grade with Mrs. Lemons' Noun Packet
Or Teaching First has a fall noun sort. (I had a hard time getting the link to work on her post. Try clicking on the picture below instead.)
Or Ladybug's Teacher Files has four cute noun posters.