The Nintendo Entertainment System or Famicom was released in 1985. Given the 20 year duration of US Patents, almost all of the original patents have expired. Does this mean that we can legally produce a clone of the system? This is an open question.

One thing is clear: all copyrights are still owned by Nintendo.

Here are some questions to ask intellectual property lawyers:

1. Are manufacturers of NES clones subject to legal liability if the patents have expired from the NES?
2. Are we subject to legal liability if we are helping programmers create new content for the NES?
3. How can we know that the NES hardware is now in the public domain?
4. Are there ways in which aspects of hardware can be covered by copyright (and therefore not fall into the public domain)?
5. In what ways can companies like Nintendo continue to receive intellectual property protection, even after their patents have expired?
6. Can a software company receive tax deductions for donating software code to a 501(c)3? (this would be useful if we wanted to license any old 8-bit software)
   

Reverse Engineering FAQ (Coder's Rights Project, EFF)
http://www.eff.org/issues/coders/reverse-engineering-faq

Incomplete Discussion of Legality of Hardware Clones
http://en.wikipedia.org/wiki/Nintendo_Entertainment_System#Hardware_clones

Many companies are now selling consoles which can play old nintendo games.
http://www.playmessiah.com/products/classics/generation-nex-videogame-console.htm
http://gear.ign.com/articles/677/677770p1.html
http://kotaku.com/385032/this-portable-nes-is-legit-works
http://www.estarland.com/index.asp?page=NintendoNES&cat=HW&product=22536&q=

Various debate about this:
http://www.gamasutra.com/features/20051111/boyd_01.shtml
http://gaming-day-japan.blogspot.com/2005/12/nes-patents-are-expired.html
http://digg.com/gaming_news/Patent_on_NES_runs_out_so_now_other_comapnies_can_sell_the_NES

Interesting Article on the 10 most important patents in Video Game History:
http://www.gamasutra.com/view/feature/1735/the_ten_most_important_video_game_.php?print=1

Possibly the NES has a BIOS that is protected by copyright?
http://www.digitpress.com/forum/archive/index.php/t-23832.html