Interesting article: http://www.dailygalaxy.com/my_weblog/2011/06/-dark-energy-is-a-fiction-the-appearance-of-acceleration-is-caused-by-time-itself-gradually-slowing--1.html#more
A radical new theory suggests that the expansion of the universe may not actually be accelerating, it's just that time is slowing down, which creates the illusion that things moving away are traveling faster and faster. I've never been a fan of the whole dark matter / dark energy explanation, it seems rather ad-hoc and like something somebody would make up. This theory, which certainly isn't generally accepted, is at least far more elegant :teddyr:
So, we're not actually running out of time, but just the opposite. This is good to know.