I hand out a jelly bean to all the students, and ask them to write in their journals for 5 minutes how a jelly bean is like an idea. (The idea that jelly beans are ideas comes from Roots in the Sawdust,edited by Ann Ruggles Gere)
I have students read their entries, and they come up with these types of examples: ideas are different flavors, different colors, chewy, some ideas are good like some jelly beans are good..etc. Some students prefer to write how a jelly bean is not like an idea (and then they come around to my metaphor)
Then I hand out a list of Emerson quotes and explain that these are Emerson's ideas. I ask students to make an Argus-like poster using one of the ideas. They can cut pictures out, draw them themselves.
Students also have to explain how the idea reflects their life in a short essay.