Cuisenaire rods can be used in many ways in the classroom. They can be used to practise speaking, reinforce pronunciation, to practise various grammatical structures and to build up stories.
I'll start with a short explanation for anybody who might not be clear what Cuisenaire rods are. They are small pieces of wood of differing sizes and colours, sold in a set. The smallest is a cube and there are various lengths of oblong-shaped wood. Rods of the same size are the same colour.
You can use them to practise comparitives and superlatives by simply comparing the rods. You can also practise "the green one" and phrases such as "could you please pass me the blue one?". You can also use them to practise questions. Make an affirmative sentence and use a rod to denote each word, you can then move the rods around and add others to represent "did, do" etc. This visual representation can help students understand the rules.
You can use the rods to represent stressed and unstressed syllables, or stressed and unstressed words in a sentence. Students can also have a go at placing the rods to denote stress. Use the smaller rods to show which are unstressed and be sure to always use the same colours and sizes to denote the same thing.
You could also use the rods to build up and represent a small town. This can then be used to practise prepositions such as "walk past the bank, through the park, over the bridge" etc. You can also build up a story with the students using the rods. One of the rods can be used to represent a person who goes through a series of events during the day. After constructing the story as a whole group, students can re-tell it in pairs or write it out.
These are just a few of the activities you can do with rods. I'm sure that once you get used to using them, you will have many more ideas.