I was just thinking about this as I have people coming round after X-mas. At the moment I'm thinking:

1. Mario Kart 8
2. Lara Croft: Temple of Osiris
3. Tekken Tag Tournament 2
4. Fifa 15
5. Gran Turismo 6

My family doesn't play any video games but they do play tabletop games so I'll list some of those.

1. King of Tokyo
2. Ticket to Ride
3. Hanabi
4. Monopoly
5. Clue

I'm teaching them a few other games as well, but they don't understand the very complicated ones so that eliminates a good many that I own.

Mario Kart, Micromachines 2 and a bunch of 2D beat'em ups.

Smash
Mario Kart
Street Fighter
Nintendo Land
and... *drum roll*
Frog Bog

Wii U dominates local multiplayer, no comparable experience in other consoles:

1- Nintendo Land
2- Mario 3d Wrold
3- Mario Kart 8
4- Smash Bros
etc...

So far this year it's been:

-Ultrastar: classic karaoke action at my house, with more than 300 songs

-Mario Kart 8: some multiplayer action before Christmas eve dinner.

-Hyrule Warriors is dominating Christmas!

It's been ages since I've played Micromachines, shame it isn't on Nintendo's VC.

Might coop Streets of Rage 2/3~

Super Smash Bros
Mario Kart 8
Mario game (3D world/Super Mario U)
Halo
CoD