Aaron-- If you're looking for a great read that entwines relativity and the current (near-current) state of cosmology, let me recommend "The Five Ages of the Universe" by Fred Adams and Greg Laughlin. In essence, the book extrapolates our current understanding of expansion, stellar lifespans, quantum mechanics and relativity into deep time. In other words, given what we know now, what happens a 100 billion years from now, or a hundred trillion years from now? You end up with atoms the size of the solar system and stars with only a few watts of output. You've got black holes fizzling away from Hawking radiation. It's written in a very approachable style that will give you grist for years' worth of headscratching conversations. Michael