I got it working in Ubuntu 13.04. I imagine it works on every version prior as well.
sudo add-apt-repository -y ppa:nilarimogard/webupd8; sudo apt-get update -y; sudo apt-get install -y pulseaudio-equalizer; mkdir -p ~/.pulse/presets; pulseaudio-equalizer-gtk
It doesn't work unless you manually create that directory above, else the GUI will refuse to launch. Quite the programming error, but the Ubuntu community just doesn't see much use for a pulseaudio-equalizer, despite how critically useful this is in getting the most out of your sound equipment.
Just remember to adhere to Subtractive EQ, as it is never good to increase dB higher than 0.