Step 1: Gather materials
One coconut shell. In two halves, with a clean break and no pieces missing. Large enough to accomodate the speaker inside.
One more half shell (optional) for the base, if you do not want your enclosure to roll off the desktop.
Step 2: Drill out eyes
Step 3: Fit bracket for electronics
Step 4: Fix the fabric to keep insects out
Step 5: Fix the speaker
I used a two component epoxy filler to seal the gaps around the speaker. Since the shell is not perfectly round, air can leak around the sides of the speaker and this will lead to a loss of volume. I used a plastic bag to isolate the speaker from the sticky compound so that the cone would not be contaminated.
The filler will have to be cut away if the speaker ever needs to be replaced. But then it might be easier to make a new enclosure, because the replacement speaker might not be of the exact size as the old one.