How to enable certain extensions while in Chrome Incognito mode

How do you enable certain extensions, like Flashblock and Adblock, while using Chrome Incognito? I don't see much of a point of incognito mode if sites can still track you using Javascript, or now show massive Flash videos and animations that bring your system to a crawl. I've actually had to force-kill Chrome a few times when it comes across a site with enough Flash ads to make it become completely unresponsive.

Right when you first open a chrome incognito window it says to you, "Because Google Chrome does not control how extensions handle your personal data, all extensions have been disabled for incognito windows. You can reenable them individually in the extensions manager."

This also includes a link to the extension manager with an option below each item to "Allow in incognito".