A recent article by R. P. Winnington-Ingram elucidates Euripides' penchant for clever "jokes" at the expense of the literary traditions or the stage conventions within which he worked. While Winnington-Ingram voices some trepidation that other critics may find his identification of such levity in a great tragedian "repugnant or even abhorrent," his assessment of these witticisms, which (in a play on the word's current and etymological meanings) he dubs "sophisticated," has offered insight into Euripides' artistry and inspired further study along similar lines, notably by Geoffrey Amott.
A keynote of the examples of cleverness noted by these scholars is their self-conscious and essentially anomalous calling of attention to tragic traditions or conventions which--to be serious--must be kept silent; thus Winnington-Ingram notes the wry humor involved when Elektra assumes that the intended murder of Aigisthus must have failed, "For where are the messengers?" Winnington-Ingram characterizes such bits of humor as clever novelties aimed at an Aristophanes or an Alcibiades, or at the younger, more restless, more sophistically oriented population in general.
I will suggest here that just such a witticism occurs in Euripides' Medea, in a dark and serious moment and so thoroughly "tucked away" that it might not be readily appreciable even by an Agathon in the audience.
McDermott, Emily A. "Medea Line 37: A Note," American Journal of Philology, Vol. 108, Iss. 1 (1987). http://scholarworks.umb.edu/classics_faculty_pubs/16
American Journal of Philology