Download UFDG-3.7/Spice3

Click on UFDG.Unix-Packet.tar.gz (~1.5MB), which you have to decompress (gunzip UFDG.Unix-Packet.tar.gz) and untar (tar xvf UFDG.Unix-Packet.tar). The resulting directory includes the UFDG-3.7/Spice3 executable, documentation, circuit simulation examples, and the UF COPYRIGHT.