Supernovae are spectacular events. The recent one, SN1987A, emitted light at a rate 100 million times that of the Sun—and it was one of the fainter supernovae. Unfortunately, supernovae are very rare. The last one seen in our galaxy was Kepler's in 1604.
By what mechanism do massive stars explode? Neutrinos produced in the core and absorbed in the outer layers play the most important role.