Aside from marking the start of a government shutdown, Tuesday is also the day that Obamacare's new insurance marketplaces open. And if you're planning to buy a health plan today, we'd love to hear from you! We're looking for people who can share their stories of buying health insurance today -- or not doing so, because they're running into some hurdles. Send me a note about your experience right here. And, if you're looking for more information about how the marketplaces work, you can read this Wonkblog explainer or check out this two-minute video.

Wonkblog's Sarah Kliff breaks down the policy you need to understand about the Affordable Care Act, from politics to premiums. (Kate M. Tobey/(In Play))