Mots melangés is a word find site for children with an inbuilt competition. Some students would like the challenge of this and they would all benefit form the vocabulary building skills. Word finds drive me nuts but my students seem to like them and so , from time to time, I give them one and 10 minutes only at a time. They learn the vocabulary well this way. An interactive version might appeal to them more and this site has very clear graphics . You can download programmes elsewhere too to make your own word finds with custom vocabulary. A good filler activity with sound outcomes. There is another online site here.