This is probably not a complete list, but here are some of the 4-Player games available on the Wii U.
(Note: Some of these games are actually 5-Player games; utilizing the GamePad and 4 Wii Remotes.)

Adventure Time: Explore the Dungeon Because I DON'T KNOW!
Cloudberry Kingdom (eShop Title)
FIFA 13
Game & Wario (not "true" 4-player, but some mini-games require "spectators" to play)
Mario Kart 8
Mario & Sonic at the Sochi 2014 Olympic Games
New Super Mario Bros. U / New Super Luigi U
Nintendo Land
Rabbids Land
Rayman Legends
Scribblenauts Unlimited
Sonic & All-Stars Racing Transformed
Super Mario 3D World
Tank! Tank! Tank!
Wii Party U

Also, coming within the next six months, we will also have:

Splatoon
Super Smash Bros. for Wii U

xD

I wasn't sure about the amiibo figurines at first, it does seem like just a physical DLC / memory card type thing. But having thought more about it it's a little more than that. Instead of buying DLC that unlocks content in one game, you're actually buying something that could unlock content in any number of games. Whether any of that content is worth it, and how many games use it, remains to be seen.

I love the idea of the Gamepad. Since the DS I've fallen in love with the two screens idea, even just something as simple as having a map always there is brilliant. Mini maps, particularly in console games, tend to be poor and nearly useless. But having a full proper map always available makes such a difference. It's a bit more difficult to swap between the Gamepad and TV then the two screens on a DS (because of the distance), but I still find it a great tool.

I'm less enamoured of the other additions, like microphones and gyroscopes. I don't think they add much, other than price.

Can you guys recommend me some games that don't look cartoony or goofy? I want to get something for my brother because he really doesn't seem to like any of the games i have and I want him to have some fun with this thing too.
I was thinking something like Assassin's Creed 3 or that Splinter Cell game but I don't know if these games can be played on their own or if the player needs to have played the previous ones in the series.
If you guys know any other cinematic "real" looking games with not too much scy-fi or fantasy in them please recommend me something nice.
I hate playing Mario Kart and Zelda, having a blast, and seeing him just holding the controller confused not knowing what to play with it.

Assassin's Creed 3 and Ninja Gaiden 3 tie too closely into the previous instalments, but...

Batman; Arkham City
Batman; Arkham Origins
Splinter Cell: Blacklist
Resident Evil: Revelations
Call of Duty: Black Ops 2

are worth a look.

Batman Arkham Origins, Zombie U, Assassin's Creed IV Black Flag, Resident Evil Revelations, Deus Ex Human Revolution. Batman Arkham City, Sniper Elite V2, Darksiders II.

http://nintendo8.com/
....

If youre into gaming for "cheap", consoles and especially nintendo stuff isnt the wallet friendliest way.

Then again, id buy super nintendo and bunch of oldies with it in heartbeat if i saw good offer ;) ive sold used computer stuff online and am actually selling atm

Sometimes you just want to get rid of the stuff and ask far less than what you could really get if you just waited longer. Cheap does not equal automatically stolen.

...you wouldnt happen to need Antec Truepower Quattro 1000W psu or Asus P8P67 Pro B3 mobo would? :)

That was a few months ago actually (More then that now that I think about it), Nintendo Network has been out since I have owned my WiiU, which was around Christmas. At least, I think that's what it does, I haven't had to transfer from one system to another, only from SD cards when I upgraded the one in my 3DS.