I think there’s a joke in Augustine’s Enarratio in Psalmum 52, but I may just be reading something into the text that isn’t there. After discussing the heading of the Psalm (IN FINEM, PRO MAELETH, INTELLECTUS IPSI DAVID), and etymologizing Maeleth to mean parturiens and dolitus, Augustine goes on to explain that it is Christ about whom the heading of the Psalm, and especially Pro Maeleth, speaks.
He then explains that it is through the members of the body of Christ that Christ Himself suffers here on earth (Christus hic parturit, Christus hic dolet) and then says what I think is the joke: caput est sursum, membra deorsum = the head is above, the members below. The joke of it is: Augustine is preaching thus far from the heading (caput) of a chapter of the Psalms and has yet to get into the body of the text (membra). It’s a lame joke if it’s a joke at all, but I think it’s there.