We value Open Source and make a point to release all our plugins on GitHub under a BSD License.
Inside MonoDevelop/Xamarin Studio, navigate to Tools → Add-in Manager.
Click the Gallery tab, then search for wakatime.
Click the Install button and then when add-in installation dialog popups click Install.
On MonoDevelop/Xamarin Studio versions prior to 5.10 you might get an error message, just ignore it.
Enter your API Key, then click Apply.
You might have to restart MonoDevelop/Xamarin Studio.
Use MonoDevelop/Xamarin Studio like normal and your stats will automatically show on your WakaTime Dashboard.