1. A look-up table (LUT) for a programmable integrated circuit (IC), comprising: a plurality of input terminals; a cascading input coupled to at least one other LUT in the programmable IC; LUT logic having a plurality of LUTs each coupled to a common set of the input terminals; a plurality of multiplexers having inputs coupled to outputs of the plurality of LUTs; an output multiplexer having inputs coupled to outputs of the plurality of multiplexers; and a plurality of cascading multiplexers each having an output coupled to a control input of a respective one of the plurality of multiplexers, each of the plurality of cascading multiplexers comprising a plurality of inputs, at least one of the plurality of inputs coupled to the cascading input, wherein the LUT comprises a plurality of output terminals coupled to the outputs of the plurality of multiplexers and the output multiplexer.