What would you say your most unusual experience while travelling has been? However you want to define "unusual."
In terms of an unusual trip or unusual overall situation, I'd probably cite my trip with my parents and brother to communist Russia when I was 5 (or had I just turned 6?) - to Leningrad, now St Petersburg.
For "most unusual incident" - hmmm. I've had a few. Perhaps being in Cairo with my American friend and some Yemeni guys who were friends of hers, and having a firecracker chucked under our feet by some idiot young guys in Khan al-Khalili market.