This is a development from the roll a plenary idea and uses the decide now app which is a free down load from the App Store.
(Click image to download)
This app is highly versatile and is not restricted to the example of plenaries shown here. In the settings section, the categories can be edited and saved to match any activity.
A bit like wheel of fortune, spinning the wheel will randomly select one of the categories whilst building an air of anticipation amongst all present.