This sample shows how to use googlemap api libraries features througt this control even when they are not totally supported by the control in a "pure mvc way".

You just need to add the library you want to use

    @(Html.GoogleMap()
        .Name("map")
        .Height(500)
        .Libraries(new [] {"drawing"})
        .ClientEvents(events => events.OnMapLoaded("mapEvent"))
    )

And then using the map event OnMapLoaded you can get a reference to the map and accomplish your task using javascript. See the view tab for more details

Drawing tools provides a graphical interface for users to draw polygons, rectangles, polylines, circles, and markers on the map.

See Drawing tools in Google for more options.