There's this book, called City of Masks (By Mary Hoffman) that talks about this young boy that "stravagates" to Venice, Italy in the 1500's from his life (around 2000, England, I recall). Whenever he slept with this certain notebook (which turned out to be a talisman in the book), he would literally "teleport" to 1500's Venice, Italy when he fell asleep.
Maybe this was taken from lucid dreaming?
Interesting to think about :P