What's your favorite local co op?

Dark souls 3 or Resident evil 6

• LEGO games
• Guacamelee
• Castle Crashers
• Rayman Origins
• Trine
• Lara Croft and the Guardian of Light

• BattleBlock Theater
• Child of Light

Castle Crashers
Critter Crunch

Magicka
Trine

Guacamelee!

Left 4 Dead 2

Lovers in a Dangerous Spacetime

Crawl

The last one me and a friend really enjoyed was "Super Cyborg".
It reminded us of our childhood gaming sessions (Contra on SNES) and it was/is quite challenging and pretty hard.
Still looking forward to check out Crawl.

isaac rebirth

LEGO games are great co-op.
Brothers: A Tale of Two Sons can be played co-op on on controller. Did that with my daughter and we enjoyed it.
Never Alone.

I know that isn't exactly what you asked for but I can highly recommend to let her play some Telltale Game (Walking Dead for example) and sit by and watch. Almost as much fun as playing it yourself. : )

For co-op: I really enjoyed playing Resident Evil 5 together with friends. Also the above mentioned Brothers and Never Alone are greaat for this.

I don't have a favourite yet, but I'm looking forward to Salt and Sanctuary, which I'll start soon ^^

Rayman Origins and Rayman Legends are pretty fun on coop

DeathSpank series.

Trine 2: A side-scrolling puzzle/adventure game which can be played by up to three players locally. Very fun little game, with good graphics style, great music, and some decent puzzles.

Grid 2: A terrific racing game which can be played split-screen against another player.

Screencheat: A local and multiplayer game where everyone is invisible, and the only way to get kills is to - you've guessed it - screen cheat. Very fun game, up to four players can play locally.

TowerFall Ascension, Helldivers, Gauntlet

You guys know what couples are playing on twitch? I don't have a big enough following yet to just play whatever I want.

Binding of Issac!

Gang Beasts is hilarous.

Tunneler, Scorched Earth, Achtung die Kurve!, Worms

Older games, but it was the last time I had any friends to play games with :-) :-(

Castle crashers and Brawlhalla,these games are so good and fun in local co-op :)

One of my favourites is Monaco. It's pretty chaotic at first (especially in co-op), but once you realize how it works it's really fun.
And I agree with Crossbourne - Lovers in a Dangerous Spacetime might be what you're looking for. I would suggest trying it first.

Not fun for GF, cuz you gonna beat sh*t out of her in this one:

Worms armageddon, Mortal Kombat, Injustice,

Fun, cuz you're going to play against AI/NPC:
Serious Sam (even splitscreen)
Left 4 Dead, Portal 2 (awesome for GF!)
Sonic All stars racing

Also Sanctum & Orcs must die is nice, but requires 2 PC :)

upd: Metal Slug 3 is awesome!