With a focus on commodity PC systems, Beowulf clusters traditionally lack the cutting edge network architectures, memory subsystems, and processor technologies found in their more expensive supercomputer counterparts. What Beowulf clusters lack in technology, they more than make up for with their significant cost advantage over traditional supercomputers. We propose an architectural extension that adds reconfigurable computing to the network interface of Beowulf clusters. This enhances both the network and processor capabilities of the cluster.Furthermore, for some applications, the proposed extension partially compensates for weaknesses in the PC memory subsystem.We discuss two applications, the 2D Fast Fourier Transform (FFT) and integer sorting, which benefit from the resulting architecture.