Can a zero knowledge proof (or MAC) be generated from human-typable input?
The usual way to encode long random bitstrings, so that they can be easily memorized and/or entered by humans, is to break them into blocks of (typically) 10 to 12 bits and map each block to an entry in a fixed dictionary of common words.  This approach is commonly used for secure passphrase generation, e.g. by Diceware, S/KEY and PGP.

Assuming an 11-bit (i.e. 2048 word) dictionary, which seems to be close to the "sweet spot" for English (in terms of difficulty of memorization per bit), you could compute a MAC of the current time using the shared secret key, truncate it to 88 bits and map these to a sequence of eight words for the user to enter.

Ps. The optimal choice of words to include in your list depends somewhat on the use case and especially the entry method you're envisioning.  For typed entry, shortness is important, whereas for spoken entry you want longer words with easily recognizable sounds.
For typed passphrase generation, I've personally found a good starting point to be the set of exactly 4-letter words in any basic English dictionary (which should give you around 2000 to 3000 words, depending on the size of the dictionary), optionally filtered to remove any inappropriate, obscure or confusingly similar words.

Edit: I didn't see your clarification before posting this answer.  Honestly, I'm not sure if the method I describe will help you in your task "to create a voting scheme that doesn't require a lot of crypto infrastructure", but then, I'm not really sure what would, either.  In the answer above, I implicitly assumed that storing the secret key and calculating the MAC would be done by a computer, with only the MAC entry stage being done by hand.  If you want the MAC calculation to be done by a human too, this becomes a very different (and much more difficult) challenge.