OK, so you want /myapp/args to be mapped to /myapp/default_controller/default_function/args. By default args would be interpreted as a function name and will be mapped to /myapp/default_controller/args. To change that you need to define a list of functions for the default controller. Then if args is not in that list it would be mapped to /myapp/default_controller/default_function/args.
routers = dict( myapp = dict( default_controller = "default", default_function = "index", functions = ["fun1", "fun2", "fun3"] ) )