Just in case you weren't aware of this a study has been released which "proves" that having caffeine before going to bed interferes with your sleep.
I did find one interesting thing in the article, apparently this side effect worsens as you age. But seriously by the time you're in your 50s I would have thought you would have figured out that if you have coffee before bed your sleep will be affected.
I guess however that the folks at the Canadian Institutes of Health Research, the Fonds de Recherche en Santé du Québec and the Natural Sciences and Engineering Research Council of Canada needed something to do.
H/t to Dr Grumpy