Quiztastic!
This is a tiny Visual Basic program, designed as a reinforcement activity for the last few minutes of a lesson. A volunteer is asked questions by the computer and they have options such as "Ask the class", "Remove two wrong answers" or "Ask a Friend". The simplest of the programs on this website but probably the most propular.
The program comes with some sample questions about the Year 11 "Earth in Space" unit but as can be seen here, it is *very* easy to add your own.
From here you can download (right-click and choose "Save Target as"):