SUPER MARIO BROS. for Nintendo (1985)
I have been going crazy looking for original SUPER MARIO BROS. nes rom file. Here it is. I use it with NNNesterJ emulator, i think it's pretty good.
Click to download:
nj051a_en.zip (227 kb)
SMB.NES (40 kb) (The original SUPER MARIO BROS. rom file)
You can find more emulators here: http://romhustler.net/emulators.php