In the photo above, I am holding two small vials of liquid metal. The vial on the right contains gallium, an element that melts at 29.76° Celsius (85.57° Fahrenheit). The vial on the left is an alloy that contains gallium, indium, and tin, and melts at -20° Celsius (-4° Fahrenheit).
You can do a lot of fun things with these. For instance, you can put a drop of gallium on a sheet of aluminum foil and it will combine with the aluminum, dissolving a hole in it. Nontoxic metal alloy that is liquid at room temperature