Another fun thing I do every week with Mr. S is our letter Caterpillar. We write the upper and lower case letter on a paper plate. I also draw some pictures of things that start with that letter. Then I help him draw the letter on the plate.
Obviously we didn't start with A. He wanted to start with T, and now we're doing all the letters in his name. He's not great at writing letter yet, but he can make a pretty good capital H. It would probably help if he would decide what hand he wanted to write with. He keeps switching between left and right. Maybe he'll be ambidextrous. Who knows?
Most of my ideas I use with my kids are from a book I bought a few years ago: Alphabet Fun For Little Ones by HighReach Learning. In this book they have various activities to do with your child centered on each letter of the alphabet. Each letter has a few coloring pages, rhyme book, language activities, science activities, small and large muscle activities, art activities, and snack ideas. I pick and choose what i want to do based on what I have available. Some things work better than others, but overall it's a fun book to have around.