wurdle ($1.99) is a fun, flexible and fast-paced word game in which you have to find and trace as many words as possible before time runs out. Can't find any more words? Shake the board to mix up the tiles! You can customize wurdle the way you like it (timer, minimum word length), and see how you measure up against your friends and the world with online high scores.
A very addictive game. The same screen multiplayer (well, two) mode works very well on the iPad. At the end of each round, all the possible words are displayed, which makes it a useful vocabulary building tool for learners. In the classroom, teachers with a videoprojector (and a VGA adapter) could organize a wurdle tournament and get pairs of students to compete in a knock-out contest.