I use Google Docs to give quizzes (I know there's Moodle, but Google Docs is very quick and easy to set up for a quick 5 question quiz).
I have my students go to ExploreLearning.com and do Gizmos on subjects we're learning in Astronomy and Physics.
I had students create podcasts to present how they would set up vacation packages to the different planets (kind of like listening to a commercial).
I am exploring ways to have the students use their smart phones (and laptops for those who don't) for polling, quizzes, and informational games.
I also have them research using laptops for in-class projects like creating scale models of the Solar System.