Huh?

Comrade PhysioProf knows his physiomotherfuckinology, but he is no economist. Can someone please explain why the fact that the Fed decided today to lend money for motherfucking free caused a sharp jump in the equities markets? As I recall, the last time a national monetary authority was lending money for free, it was in Japan, and it was the beginning of a decade long L-shaped recession, right?