© PA Photos
Michael Turner headed home 11 minutes from time to earn the Canaries a well-deserved point.
The Belgium international went close to doubling his tally late in the first half, but his left-footed effort from close range was deflected wide.
Martin O'Neill's men made a dreadful start to the second period, as Joe Bennett was shown a second yellow card within seven minutes of the restart for pulling back Elliott Bennett on the halfway line.
The Villa defender had earlier picked up an equally soft booking for a foul on Hoolahan in the first half.
Norwich began to use their numerical advantage well and laid siege to the Villa goal.
Hoolahan was again denied by Guzan - as was Grant Holt after being put through one on one.
The equaliser deservedly came on 79 minutes, as Turner rose highest to plant Hoolahan's whipped corner beyond Guzan at the far post.
Villa, who are now winless in six games, were booed off at the final whistle.