Simply define a route matching any path at the end of your routes
file. Do not forget to define specific routes for your assets though, for example:
GET / controllers.Application.index
GET /some/path controllers.Application.someHandler
...
# End of file
GET /favicon.ico controllers.Assets.at(path="/public", file="img/favicon.ico")
GET /$file<(css|img|js|partials)/.*> controllers.Assets.at(path="/public", file)
GET /$path<.*> controllers.Application.catchall(path)
Any URL not matched by an earlier rule will be matched by this one.