Irony anyone?  This week, Microsoft is hosting “Imagine 2011,” a marketing leadership summit at its Redmond, Washington headquarters.  Late last night, Microsoft’s global marketing head announced she will be leaving the company.

Mich Mathews, a former General Motors employee, has been with the company since 1989.  After working as a UK consultant for the company, she started full-time in 1993.  As she worked her way up through the ranks she was responsible for internal communications as well as advertising and public relations.  Currently, Mathews is responsible for over $1 billion of marketing for Windows, Bing and Xbox.

She will be helping Microsoft’s COO and CEO find her replacement.

In speaking to Ad Age, Mathews states that she made her decision over Christmas, and that she simply wants to break it up and start a new part of her life:

“Twenty-two years in one place … I feel like I’ve done so much” and “frankly it’s time to do something new. It’s half a lifetime. Microsoft was chapter one and it’s time for a chapter two.  It’s going to be awesome to actually get off the grid.”

She will definitely be taking a break for a while, and surveying her options.  “I am going to talk to a lot of people, return all those calls I’ve never returned, take the summer and dive into something probably around the fall time frame.”