To create a stand-alone (self-running) questionnaire...
Copy the RiddleMeThis application (RiddleMeThis.exe under Windows, RiddleMeThis under Mac OS) into the Questionnaire's folder.
As of version 2.1 (final) RiddleMeThis now comprises an application or executable and a folder with two files in it. Both RiddleMeThis and the folder (with its contents) need to go into the questionnaire's folder to make a standalone, or RiddleMeThis will not run.
When you double-click on the copy of RiddleMeThis it will automatically run the questionnaire. You can rename the copy of RiddleMeThis and/or create a shortcut (or alias) to it to make it easier to launch.