I use the Stretchy the Word Snake mat during my Guided Reading Groups. We build words in the boxes and use the little cars (look closely under the letter m and you will see one) to drive slowly as we say each sound. They we drive our cars faster as we blend the word together. The kids love this activity. Note: if you are building a word like ship...the digraph /sh/ goes in one box because it makes one sound.
Once we've done this lesson several times I place the materials in our word work center so that the kids can do it on their own.
You can download a version of this in both color and black and white.
The kids also love this center for Popcorn Word review. They get to be word detectives. They use a magnifying glass to read and record their popcorn words. Laminate the sheets with the popcorn words on them and then have the kids use a magnifying glass to read the words and record them on their recording sheet.