It was just announced today that funnyman Jerry Seinfeld was hired by Microsoft to be one of its key celebrity pitchmen in its new $300 million ad campaign. In an attempt to take on the longstanding Mac vs. PC ads with rumored slogans like "Windows, Not Walls," Jerry will appear in ads alongside the new retiree Bill Gates. Kinda ironic, no? What's even more ironic is the fact that Jerry showed off a Mac in his apartment all throughout the days of Seinfeld! What the. . .