April 14, 2001
The complete NES version of Tennis is featured in all versions of the game as an unlockable mini-game. It can be obtained in various random ways such as Tom Nook's Monthly Raffle, Crazy Redd's, as present from a neighbor, treasure hunts, birthday presents, etc.
See here for other NES games included in the game.
Copyrights for both series are held by Nintendo.