Download Blockfish:

Compressor with a bite

Blockfish by Digital Fish Phones is a free compressor VST plugin with countless ways to shape the incoming audio signal. Unlike many other software compressor plugins, Blockfish has its own distinct sound. It likes to bite, but it can be tamed easily once you've learned how to use its potential. The Blockfish compressor is by no means the most transparent freeware software compressor out there, but sometimes that's exactly what you are looking for!