Today's app, iCardSort, is one of my "teacher apps," those apps that help me manage some of the day-to-day duties of being a teacher. This app allows you to create decks of cards. The cards can be color coded, and sorted. I like using this app to sort my students into groups. You can also make notes on each card, which is nice. Below are some screen shots of my color code cards, ordered and grouped.
Although I haven't used iCardSort directly with students, there are many ways you could. Click here for some ideas to get you started.