Even though I had an N64 during my childhood, and had a blast with that thing back in the day. I would never reccomend getting one nowadays. Besides classic N64 games selling for insanely expensive prices, that trident-shaped controller, although a neat design, just has the most horribly shitty controllstick I ever experienced on an official console. The stick itself just feels uncomfortable to the thumb, and can easily get so loosened, that you really have to push it hard, to make it fully go into any direction.
So better off emulating it, using some controllers with an actually good and comfortable controllstick.
But as for games to recommend:
-Would definitely give the 'Ocarina Of Time' a try. Just to see what the hype was about, and to see for yourself if it still holds up today, like a lot of hard-core Zelda fanboys claim.
-If you're gonna try some games out with 1 friend, should absolutely try Mario Kart 64. Can also race or battle with 3/4 players, but only clear the game's cups with 1/2 players.
-If you want a neat shooter, either singleplayer or multiplayer/splitscreen, 'Goldeneye' (James Bond) is an absolute certified classic, even though I didn't play it back in the day. I had Turok 2 at home instead (also a pretty cool FPS for the N64).
And some other titles off the top of my head:
-F-zero X (futuristic racing with dope rock/metal soundtrack)
-Extreme-G (futuristic racing with dope trance/techno soundtrack)
-Super Smash bros (the first one!)
-Starfox 64 (for some 3rd person shooting, weren't that many of those on the N64)
-Banjo Tooie (absolutely charming in the sound departament)
-Mario Party 1 or 2 (wouldn't bother if you'd play these games alone, would be pretty boring without good company)
