Not as spectacular, but 4 years ago when I arrived at SF airport after a 11 hour trip the immigration officer asked why I was there. I told them I was visiting a software conference. To my surprise he then asked me to write 16 in hexadecimal. Luckily I didn't screw up.

I asked him how come he knew about that stuff and he told me that in a former career he was working in IT as well. I thought it was funny.