Gaming Good multiplayer LOCAL game

[Snappo]

You could play SSBM on Dolphin, but you need a plugin, and you need to downlaod the melee ISO.

 

[chA1nBull3t]

Get a NeoGeo emulator and download some pack of roms for it!
I had some pack, and it was full of awesome arcade games, and I used to play it with a friend of mine on the same computer all the time.

^This.
Oh man do I remember the days when me and my bro would cram one keyboard and rock some shmups and metal slug.
I gotta get me a cabinet sometime.

Don't forget about MAME either!

 

[stinkoman]

64digits, gamemakergames, and a few other websites that host games made in game maker have tons of 1 pc multiplayer games. Google them, but you'll have to sift through the garbage on gmg, 64d was much more popular, it's practically dead now.
If you don't feel like looking, you could try Super Mario Wars, Mugen (Awesome customizable fighting game, you'll need characters, if you want, I can give you my setup, but it's a large file.), or some indie games.