I wasn't too happy with any of them and thought I'd share what I came up with after some tinkering.
For the impatient:
To install required tools:
sudo apt-get install sox
To test:
play vuvuzela.wav vol 0.9 bandreject 116.56 3.4q bandreject 233.12 3.4q bandreject 466.24 3.4q bandreject 932.48 3.4q bandreject 1864 3.4q
The test file can be downloaded here.
My starting point for this was a post by Russell Beattie, where he describes his attempts at using SoX.
You can test both approaches (using an equalizer vs. using a band-reject filter), and I think the latter does a better job. I also used slighty more accurate frequencies as suggested here and added an additional lower resonant frequency at 116.56 because I could still here a faint toot.
Russell chose to use Octave to define the width around the central frequency that is removed (.1o), whereas I prefer using the Q-factor as did the original German Blog post on this subject (3.4q)
To use:
rec -d|play -d vol 0.9 bandreject 116.56 3.4q bandreject 233.12 3.4q bandreject 466.24 3.4q bandreject 932.48 3.4q bandreject 1864 3.4q
Assuming your default sound input source is the your line-in or tv-tuner.
Updated: I updated the fundamental and harmonics as per this site.
Updated again: The above update should have been better, theoretically, but it isn't.
Vuvuzela Frequencies
Fundamental: 232.4 Hz
Harmonic 1: 464.8
Harmonic 2: 697.2
Harmonic 3: 929.6
Harmonic 4: 1162
Harmonic 5: 1394.4
Harmonic 6: 1626.8
Harmonic 7: 1859.3
