ShowHopping uses data from Last.fm to map out upcoming concerts and live shows on Google Maps. Users can search by location and radius, or have the browser give their current location, and the web app will map out all live shows in the area within a defined set of dates.
Band or artist names can also be entered to narrow the search, and multiple names can be searched at once to make things easier.
The map view is a quick way to see how close upcoming shows may be, but the real gem here is probably the slide-out list view. In the list view, shows are grouped by venue and ordered by date, making it easy to scan through and find your favourites.