Memory Bank: Gnip-Gnop (1971)
But other than that factor, we had a good time with the back-and-forth. The problem, of course, is that (unlike most video games...) Gnip-Gnop doesn't really develop in any way. And skill doesn't really play into it, either, like it does in ping pong. So after awhile, Gnip Gnop sort of loses its appeal, and just takes up a lot of space on the shelf.
The nostalgia factor is high here if you grew up with Gnip-Gnop, no doubt, however. Below is a commercial for the game from the early 1970s.