This tutorial from Indiana University on recognizing (and avoiding) plagiarism is wordy, but the "Examples" and "Practice" sections in particular would be useful to students.
This tutorial from the Colby, Bates, and Bowdoin consortium walks through academic honesty issues in a way which might be more engaging (and more detailed) than a short policy statement could be. Part of a larger "plagiarism resource site."
An experiment analyzing over 1,200 undergraduate papers at a selective liberal arts institution found that requiring students to complete a tutorial on academic honesty substantially reduced the likelihood of plagiarism.
Interesting and even-handed review of a site providing programming tutorials designed for academics in the humanities. Might be some interesting inspirations here for a winter break project!
A collection of Google Earth map files, designed to help students think about the geographic locations in various literary works (and the travels of their characters). The site also includes links to some good Google Earth tutorials.