I hear what you're saying: Why not just close Outlook for an hour instead of running a new program to essentially do that same thing? Well, Email Prioritizer can be configured to let high priority messages through -- it's like call screening for email. You can let through, for example, messages from your manager, e-mail from people you're meeting with soon, mesaages with certain words in the subject line, and more. The filtering system is actually quite powerful and definitely makes Email Prioritizer a worthy tool.
Unfortunately, the program requires Exchange Server, so you can only use this at work -- not at home. It's free and comes from Microsoft Office Labs, which has also brought us cool stuff like the awesome Forgotten Attachment Detector.