We have had night time visits by a group of high school students and their teachers and from a group of amateur astronomer, both from Denmark. The groups were assisted by our own students and the visits were very successful and both groups actually prepared web pages, see
http://www.odder-gym.dk/studietur2006lapalma/index.htm(only in Danish), and
http://flastro.dk/lidemark/NOT/not_en.html(both English and Danish versions) about their experiences.