Sometimes, when travelling between places, (particulary driving) I would like to get/see/do something else on my way. Most map tools (eg Google Maps) provide a way to search for points of interest of a particular type (eg Supermarket, Swimming Pool, etc) in a specific area. They also mostly offer some kind of route planning serivce.
What I'd like to know is if there is a route planning tool/service that lets me combine the two - ie "All Chinese restraunts within X km/ Y Minutes of route". Answers that work anywhere preferred, although answers for tools with limited geographical availability would also be helpful. Bounties will be awarded for anything that can do the same for public transport journeys.