Script for wrapping at in a function. This fixes the garbled time in most cases.

at.sh

function at {
  unset IFS
  MOMENT=$*
  AT=$(which at)

  # First try at to see if I finally figured out to produce non-garbled time
  if ${AT} ${MOMENT} 2>/dev/null
  then
    # worked allright, we can exit
    exit
  else
    # We produced garbled time (duh), so let's fix this with date
    MOMENT=$(date --date "${MOMENT}" +'%Y%m%d%H%M')
  fi

  # and try again
  ${AT} -t ${MOMENT}
}

Check http://steviethecat.tumblr.com/post/134525621571/non-garbled-time-with-at for a description.