Swami Nikhilaananda said:
"Ah yes, the good old days"
When I was young, I used to love playing games like Super Mario and Super Contra.... and an endless array of games of that type - Come on, you all know that type. They used to be ubiquitous till the computer came along with its MS DOS games like Prince of Persia and Bouncing Babies. Anyway, if you played those games before and miss playing them, below is a way of reliving those good old days.
Steps to play TV Video Games on your computer
This is basically what runs your game. Here is a link from where you can download the emulator. This is just one that I found and used and it worked great. There might be others too. If you find something that is much better than this one, please leave it as a comment. I will add it to a list.
If you have an Android based phone (touch based esp), you can download an app like Nesoid Lite. It is my personal opinion that you can play such games and enjoy them more on your phone than on your computer.
We used to insert cartridges and play games. Now, you can do something similar - Download them and open the files with the emulator above. Here is a link to do that. You can perhaps find others too. If you do, please leave some links in the comments. I will add it to a list.
If you are doing this one the phone, copy the game to your memory card.
Note: Download the ones under NES - The emulators that I have specified here are the ones that can play NES ROMs.
3) Third, Play the games and have fun
It's straightforward - Just open the game files with the emulator and play :-)
Here is the direct download link for Nesoid Lite. Open your bar-code scanner in your phone and scan this.