Depending on the age level (not just ability) of the students with whom you will use this activity, "Word Mine" is a great warm up to use in light of current events, holidays, or other topics within or outside of your immediate lessons to reinforce ideas.
If you are an elementary literature or language arts teacher, this game is fun with words like "HALLOWEEN," "THANKSGIVING," or "CHRISTMAS" right around those holidays. You can always make a game of who can find the most words, longest words, etc.
Other than such obvious examples, I've done this as a warm up when substitute teaching with students' names in the class (they LOVE it) or the principal's name (they love this even more) and characters names or places in the book the class is reading. I had one class of 5th graders that liked this game so much (the competitive part of finding the most words was what kept them going) that they started supplying long words to put on the board.
The possibilities are almost endless and I think you'll find that your creativity will flow based on the response of your students. Make it fun and slightly competitive and they will enjoy it very much.
The link below gives several ideas and includes how many words can be made out of each example.