Construct a Word is a good online activity for elementary school students to use to develop their vocabulary and their spelling skills. Construct a Word, produced by Read Write Think, asks students to select the ending (not necessarily a suffix) for a word. After selecting an ending, students have to select from a bank of letters and letter combinations to form a word. Construct a Word tells students how many words can be formed from the letters available to them. When a student has created all of the words possible from the available letters, he or she moves on to a new new bank of endings and letters.

Here are some screenshots of Construct a Word.

Applications for Education
Construct a Word is a nice interactive activity for elementary school students. Construct a Word is design to be used as an individual activity, but it could also be used as a group activity on an interactive whiteboard.

Here are some related resources that may be of interest to you:
Ten Spelling Games and Lessons… And a Laugh
Five Great Grammar Resources