Can someone explain Catholicism to me please..just a quick run through?

Might sound goofy but I am curious... I was raised as just plain non-denominational christain (well I guess baptist)... raised by my father.. my mothers side immigrated from poland long before my time and they were all catholic.. my grandpa on her side is catholic also.. i just want a quick rundown on the religion to see how it differs from plain ol' christianity.. im curious to see what its all about.. thanks! :-)