I am using the matplotlib library inside Canopy, and the specific function is xkcd(). This function uses a specific font to plot charts. The font is Comic Sans MS, which if
After a lot of research, and not finding anybody who could help me with my question, I was able to answer my own question. This is what I did:
First, I found exactly where all the fonts are in within matplotlib in the virtual environment of Enthought Canopy:
luis@luis-VirtualBox:~$ find -iname '*.ttf'
A long list is generated, with results similar to this:
./Enthought/Canopy_64bit/User/lib/python2.7/site-packages/matplotlib/mpl-data/fonts/ttf/Vera.ttf
./Enthought/Canopy_64bit/User/lib/python2.7/site-packages/matplotlib/mpl-data/fonts/ttf/VeraMoBI.ttf
./Enthought/Canopy_64bit/User/lib/python2.7/site-packages/matplotlib/mpl-data/fonts/ttf/STIXGeneral.ttf
./Enthought/Canopy_64bit/User/lib/python2.7/site-packages/matplotlib/mpl-data/fonts/ttf/STIXNonUniBol.ttf
./Canopy/appdata/canopy-1.1.0.1371.rh5-x86_64/lib/python2.7/site-packages/canopy/resources/fonts/Inconsolata.ttf
I could not see the 'Humor-Sans-1.0.ttf' file/font anywhere, so I manually downloaded and copied it to the directory:
./Enthought/Canopy_64bit/User/lib/python2.7/site-packages/matplotlib/mpl-data/fonts/ttf/
Still, the chart was defaulting to another font:
Font family ['Humor Sans', 'Comic Sans MS'] not found. Falling back to Bitstream Vera Sans (prop.get_family(), self.defaultFamily[fontext]))
Then I noticed that the font I had downloaded was 'Humor-Sans-1.0.ttf' and the error messages was referring to 'Humor Sans' and 'Comic Sans' (without the 1.0 appendix). So I made two copies of the same file, inside the same directory and called them 'Humor-Sans.ttf' and 'Comic-Sans.ttf' respectively.
Next, I found where the matplotlib fontCache list resides within my virtual environment:
luis@luis-VirtualBox:~$ find -iname 'fontList.cache'
./.cache/matplotlib/fontList.cache
Then removed the cache:
luis@luis-VirtualBox:~$ rm ./.cache/matplotlib/fontList.cache
After that, I opened my Canopy Editor, opened an iPython notebook, wrote some code, plotted some graphs, and presto, my fonts were right!

Not the most elegant solution, but it worked for me.