Not an astronaut but a couple who had been working on the Antarctic (he was a driver, she was working in the kitchens/cafe/bar) during the summer season.
They had loads of really interesting stories and it sounded fascinating. They'd talked about how those who had done the winter season (24 hours of pitch blackness for 4 months) were all a little bit on edge and twitchy.
The weirdest stay-over that I ever had was a Korean religious pilgrimage who mistook me for a monk because apparently one had lived in my apartment before I moved in.