Pour liquid nitrogen into a metal cup. Atmospheric oxygen will condense on the sides and drip off. Catch the drops with a paper napkin. Set on fire. Repeat.
Nitrogen boils at 77 K (-196 °C, -320 °F). Oxygen boils at 90 K (-183 °C, -297 °F). Liquid oxygen is dangerous stuff. Put it in contact with a fuel source like carbon and you have the potential for extremely rapid combustion. The napkin burns so fast it screeches.