Concept circles (or concept maps) are a terrific, versatile graphic organizer that can be used with any age group.
Commonly, they are used to determine "which item doesn't belong." Using the board, an educator writes a word on the line below the circle. Within the circle's four quarters, the educator writes three words that are related to the main word, and one word which is unrelated. Students then determine which of the four words within the circle is unrelated to the main word.
Another use for concept circles is for students to create their own definitions of words, or clues that remind them of the word's meaning.
Concept circles are also useful for social studies. A concept circle might use "France" as the main term. Teachers instruct students to fill in the quarters of the circle with things associated with France (Paris, cheese, wine, etc.). Likewise, the concept circle can be a "which one doesn't belong activity" (circle quarters with terms like cheese, Paris, and wine, along with a doesn't-belong term such as Ural Mountains).
Be creative, involve the students, and have fun!
