We're going to have to go on record and claim that the Pong wristwatch
still looks to be the smallest iteration of Pong
that we've seen to date, but we'll let Ronald Dekker shakily hold the record for the smallest version that's easily channeled to a TV set. Nevertheless, the µPONG creation is indeed quite diminutive, using just "an eight-pin PIC processor along with two potentiometers for the bat controls, just as the original." Per usual, the circuity
knowledge used to actually assemble this thing is a hair beyond our realm of expertise, but judging by the extensive lineup of graphs and figures shown in the read link, those even partially in the know may be able to pull something similar off themselves.