Imagine you can send an SMS message to an Outlook contact directly from outlook. Despite there are some Outlook Add-ins those allow to do that, why don't build by your own. All you need are VSTO and GSM modem, either dedicated GSM modem or a mobile phone that can be connected via COM (via USB, Bluetooth...

An example of Outlook Add-in using VSTO. This is a small add-in that can speak up your email message. Used Text to Speech (TTS) library is Microsoft Speech API available in .NET Fx 3.0 or later.

A sample project with VSTO Word Add-In, Web Service, and LINQ to SQL.