Just a little about setting up Mupen64plus, the Nintendo 64 emulator.
It seems this puts files everywhere and none of the Ubuntu places that are suggested in most tutorials.
So easiest after installing the deb file, do a search in the Nautilus file manager for Mupen64 and watch all the places its stuck itself show up.
Install the frontend "M64py" to make it a little easier to point to where the Rom's are stored along with where the executable is and Data files / Plugins. Leave the search results handy so you can see where everything is.
One problem I had was setting up my controller. I used a Xbox360 Pad and tried to follow the joystick setup walkthru that is an easy find online.
https://code.google.com/p/mupen64plus/wiki/ControllerSetup
Two things to point out about this, the config.ini file it talks about is in the $HOME/.config hidden file in your home directory.
(Dot). files need to be seen in a folder by going to the menu bar and selecting View then scrolling down to hidden files and selecting so they are shown. There also may be other config.ini files for other emulators there also.
This file is nice to view and only needs a little amending (as root).
The parameter needs to be changed in the Core section of mupen64plus.cfg. It should look something like this:
Joy Mapping Stop = "j0b10"
That's for joystick 0, button 10
This gives you an ESCAPE from the emulator mapped to button 10.
The InputAutoCfg.ini file which is the file used to set various joypads up was harder to find thus the Nautilus search. The controller Setup info was wrong for me. I found it at /usr/share/games/mupen64plus
Before I go any further I have to say I had lots of trouble getting the controller to work until I realised my controller itself was not connecting correctly. I was forced to try a few different USB ports for it to connect. I checked that the system was seeing it by doing a lsusb command at the terminal until it showed up.
I grabbed the Xbox 360 controller configuration file and pasted it into the InputAutoCfg.ini and tried and tried to get it to work with the controller setup GUI in M64py frontend. No luck
Finally I found a post on the Ubuntu forums that had the answer. Call the programme from a Terminal window. I did this and all the setup configuration options were there to be changed and saved. easy when you know how.
One final thing I've been finding with emulators in general. Quite a few I've used have been opening in full screen and I've had trouble escaping from the full screen view.
There have been some quite bad tempered replies to posts from people who had this problem from some unsympathetic dicks. They should just be nice and tell them on some emulators to escape full screen it is ALT and ENTER. Even with random pushes that was hard to find and when its buried somewhere in the midst of a manual its even harder to work out.