Radial menus, or the pie menus made by designer John DiMartile demonstrates an interesting wheel-based UI for Bing Visual Search, the feature for discovering subjects and topics. John notes,
Tasked with coming up with a compelling way to search through images on the new Bing search for Microsoft, we came up with several concepts and designs. The route I took was based on the concept of the Volvelle. It gave easy access to get to related content, as well as built you a trail of volvelles to see how your choices linked back to the original starting point. I designed and animated this concept, as well as animated the rest of the concepts for presentation purposes.
A radial menu has many advantages over the traditional list-based context menu, but for has seen little adoption beyond video games.