I posted here a couple of weeks ago that "The Boyfriend" for me was a turning point in the show-- the point where it jumped to a new level of cleverness that set it wayyy apart from any other show on TV at that time.
TV Guide thinks so too! Here is their description of the episode:
How do we treasure "The Boyfriend"? Let us count the ways. This is the episode (first aired Feb. 12, 1992) in which Jerry "dates" former baseball star Keith Hernandez, but loses him to Elaine; in which George tries to keep his unemployment benefits by fabricating a bogus job selling "latex-related products" at "Vandelay Industries"; in which Jerry sneers "Hello, Newman" for the first time; and in which Kramer and Newman (Wayne Knight) unveil their conspiracy theory in a brazen satire of the JFK-Zapruder film. Just about every other sitcom prays that it could, in its entire run, come up with as many time-capsule highlights as this two-part episode contains.