Crosswords are great time-killers, especially when travelling. I have not tried this one out, but Crossword 4X4, developed by a small 2-man team, is available for free in the app store, so go grab it here. The game features 22 levels and over 148 words, with an easy to use touch interface to switch between clues and words....

Fun and Free
The game is pretty good. If you like crosswords or word games I would recommend this.
Fun and Free
The game is pretty good. If you like crosswords or word games I would recommend this.