Wordle.net is an amazing word cloud site. You can either take your own text or copy paste text into a box and magically a word cloud appears. You can adjust the colors and fonts. I think this is a great tool for educators. In an English class, students could describe the character in a book using adjectives and then make a word cloud from those adjectives. In science, when you are learning about a theory students can make a word cloud of all the words associated with that theory. In math, when learning a step-by-step procedure, say solving linear equations, the students could write out the steps and word cloud them. When teaching rules and expectations to students, students could list all the words associated with the rule or expectation and word cloud them. Word clouds are not only educational tools, but they make for a great display of student work in the classroom. It conveys student knowledge and is appealing at the same time. Have your students create a word cloud through wordle or on paper.
Here are some examples of word clouds from wordle: