One from the department of wacky but intriguing ideas:
I recently tweeted a couple of links (Mail Online, National Geographic) on whether a large meteorite hit the Gulf of Carpentaria around AD530, and the resulting debris caused global cooling in the northern hemisphere with crop failures, possibly increasing the pressure on the peoples who became the Anglo Saxons to migrate to England from Frisia and also that it was easier for them to establish and expand their poplulations as the British successor states ability to resist encroachment was reduced as the result of famine.
As I say, intriguing. If as has been suggested, the plague of Justinian had had a greater impact of the British population because of greater exposure through continental trading links, it could just be so - sick and starving versus just plain starving.
What I also like is the rather cool way it ties Duane Hamacher's apparently unconnected research into the recording of astronomical events in Aboriginal dreamtime stories, and shows that all knowledge is useful ...