I just remembered this and dug it up from my journal. It took place in January of 1998 in the waiting area of an airport gate (presumably in the MSP airport, waiting to return to Seattle). I recorded it shortly after witnessing it firsthand. I reproduce it verbatim here. It is completely true.
A young boy climbing all over his mother repeatedly saying "I'm going to marry you." Then he says "Boys marry boys and girls marry girls." I don't know if this is an accidental or intentional inversion, but he finds it highly amusing and repeats it many times. Then it seems he realizes that according to this new mantra, he can no longer marry his mother. So he accosts his younger brother (his father is there too) and says he's going to marry him. The younger brother has not been following the earlier marriage declarations, so doesn't really know what to make of this. After repeating "I'm going to marry you" and "Girls marry girls and boys marry boys" to his younger brother, our protagonist loses interest in his unenthusiastic fiancé and returns to his mother. "I'm going to marry you." he begins to repeat while climbing all over her. But how does he reconcile this with his oh-so-amusing motto about same sex marriage? "I'm a girl!" he declares with delight. "Boys marry boys and girls marry girls. I'm a girl. I'm going to marry you." This continues in a most amusing fashion. Mother seems mildly amused and affectionate. Father is lock-faced, pretending not to hear. Younger brother is amusing himself in a different play universe.
A lot of Freud's contributions have been surpassed, overturned, or discarded. But he wasn't totally smoking crack. What strikes me in this scene is the ease with which the boy discarded his own gender in order to enable him to fulfill his marriage wish within the framework he had established. That, and the pleasure he takes in discovering a solution to his problem. I seem to recall the father had his face in a newspaper the whole time. And the younger brother was on the floor, plaing with a truck. This scene still amuses me when I think about it, over eight years later.