Hmm, I don't know if I should take this seriously or not.
Cause if I can be a little silly about it: We tried something a little "Exotic" and we left a Moody Blues record on, "In search of the lost chord" to be exact and during "Legend of a Mind" we were flying around in Timothy Leary's astral plane whilst doing it.
If you want seriousness not involving old bands that only I know of and exotic mind tweakers, I'd say the weirdest place was probably, and you'll see why I picked the sillier route because I know this isn't the strangest place one can do it, but out in a park pavilion after hours. We actually passed out in the middle of a hedge and then when we woke up it was past the hours they normally let people in, so we exploited having the night on our side.