For something strange the best subjects would fall under paranormal
Things.
It is best to talk about something you are interested in and have some knowledge about because then you have a comfort level and sound more like you know what you are talking about.
Some topics under paranormal include:
Ghosts, spirits, orbs
Shadow people
People spontaneously combusting
Aliens, ufos
Crop circles
Cow mutilations
Chupacabras
Bermuda triangle
The big foot scam
http://www.ghosts.org/genpara.html