Ring words are words written on index cards and strung together with those small metal rings. I do six at a time, and they're great for rhyming words. I've also done them for blends, like words that end in SH (ex: wish, fish, dish) or TH (math, bath, path).
Like all my other Language Arts activities, the children write the words in their writing journals. Six is max for this activity, which gets hung from the ceiling when we're finished.
Don't be surprised to hear the students reading the words aloud at odd times during the day.