Crossword puzzles are still used in schools around the world. Great tool to use for review and for introducing new terminology/skills.
Here are a few sites that create crossword puzzles for your students or teacher professional development in several different formats....better yet, have your students develop the crossword puzzles for their peers.
1. Discovery School's Puzzlemaker this is great site that is a free puzzle generator tool. "Create and print customized word search, crossword and math puzzles using your word lists."
Some of the puzzle types available for you to create: fallen phrases, letter tiles, cryptogram, double puzzle, math square, number blocks, criss-cross puzzle, hidden message, word search and mazes.
4. XWORD puzzle generator a cool little website that is setup to create interactive crossword puzzles that are saved as a webpage where the user can then input the characters to solve the puzzle.