Although Audacity works for this, it's a bit on the overkill side with all the features and controls. If you're using Ubuntu, try audio-recorder. It will record anything that comes out of your speakers. You can select Custom Audio Device and then, under Device settings, select Built-in Audio Analog Stereo (Microphone).
When I get stuck on any audio source, I circumvent the problem. I record the audio using my (standalone) Zoom H1 stereo digital recorder (plugged into the headphone jack or audio out of the source device). It will save the audio on its own micro SD card as wav or mp3 files (with lots of quality options). Then, I just copy the files to wherever I need them. It's an extra step and another device to buy, but it works wonderfully and is useful for a lot of other things.