Strontium is used as an X-ray supressor in the glass of the color cathode ray tube (CRT) in color TVs and video displays. (Note that the CRT is waning in popularity as technology advances.) It also has other applications in the manufacture of alloys, some of which are eutectic. Salts of this metal are used in pyrotechnics and flares to impart a specific color to the flame. The metal has four stable isotopes, but also has a number of radioisotopes that find a variety of applications in nuclear pharmacology. And the value of these radioactive isotopes of strontium also extends to uses in both medical and other biological research, and as a heat source in the manufacture of thermoelectric generators.
Wikipedia has additional information, and a link to their post on this interesting metal can be found below.