How should I go about finding people to play-test my video game in such a manner that I can observe parts that frustrate them? The only gamers in my family either A. live out of town, B. play only M-rated military first-person shooters for Xbox 360 published by Activision despite not being near old enough to buy M-rated games, or C. don't feel like testing a new version of a game whose previous version(s) they have already tested. Sometimes, I've tried asking on #nesdev on EFnet, but at some point channel regulars want to quit hearing about it, so I've had to learn to ask only once in a great while.
EDIT: On second thought, I guess the presence of category C means my game sucks, but I have no place to start on why or how I could fix it.
You could try to set up a live meeting with tinychat/skype/whatever with someone. There are several programs that allow people to broadcast their desktop as a webcam so you could watch live emulator feed. Coupled with a mic they could tell you what's frustrating about your game almost instantly.
I imagine you've tried Nintendoage? People there seem to jump at the chance for testing opportunities.
What sort of game is it? If it's a platformer or adventure game I'd be willing to test it, and perhaps dispense more feedback than you would even want. If it's not... I probably won't like it on principle.
If your game is no good, you should ask people what thing they dislike, so it can be corrected.
If some parts frustrate people, ask them what it is? If you only changed part of a game, and that part tends to be frustrating, you could provide save state files for those things.
Some people might be able to make recordings in an emulator or on a VCR, and then provide comments.
You can also provide comment forms on a download area, so in case someone finds the game the first time, they can write a comment after playing that game. (Include the version number of the games with the comments)
Some of the things I have written here assume it is NES games. For other games of course it would be different.
Maybe you have already done these things, too; I don't know. I also don't know if it is exactly what you are asking.