When I suddenly fall ill, or otherwise don't want to take 10 hours to plan a sub lesson, I usually go online to http://puzzlemaker.school.discovery.com/ and plug in some vocab words for some puzzles (they have some pre-made banks of words also!)
I make four puzzles using the exact same list of words. I usually start them with the word search (even non-readers can do this!) then go on to word scramble, then crossword. This because they need to know the words pretty well by the time they get to the crossword - also, the word search has the word bank on it.
Then, the first 4 students done with each type of puzzle get extra credit or small prizes. This works best with life science because there is a lot of vocab, but you might be able to use it for other subjects as well.