ha, yeah I've done that a couple of times, mainly when I have taken my book to work to read on my dinner break and forgoten to take it home and I have nothing to read a chapter or so from before I go to bed so I start another one.
It can be confussing at times though, if you are reading books of similar genres, as I remember reading two books at once and I was left wondering where a character had dissapeared to only to remember he was in the other book I was reading at the time
