On the LHC thing, before they switched it on people spread rumours that the energy levels would create mini black holes.
The energy levels were many orders of magnitude lower than needed for that, but I seem to remember that the media found the odd rogue scientist who refused to rule it out. (because actually, you could not rule it out as a quantum effect).
On the wider pont.. Dunno really. I'm sure there is more to the universe than what we know today.
The balance of probabilities suggests there are alien life forms out there, though on the Stephen Hawking thread there is a quote about it not being a good idea to go looking for highly advanced, space-travelling aliens.
Yeti/Bigfoot. Perfectly possible that a large ape-like creature lives in small numbers in remote parts of the world.
Ghosts... Hmm not really. There have been lots of efforts to find hard evidence. Not successful.
Generally fairly open-minded, unless the evidence has already ruled it out.