Mario-Bros.-Dis
This is a byte-to-byte accurate disassembly of Mario Bros. (U) for NES. It's not fully documented, so you can contribute by sending pull requests or something.
I didn't included graphics data for it, you'll have to get it yourself (you can use included python script under "misc" folder to rip graphics from the ROM image).
Assembles with "CC65" compiler/assembler (there's also asm6 version if you want).
TO DO: -Disassemble "Classic Serie" version. -Add support for European and GameCube versions