Wouldn't you know it? I just got my laptop back from getting fixed because it was locking up. That problem was fixed beautifully, but the shop must have done something to mess up the headphone / audio output jack which I never thought to check.
I set up my seminar and plugged my external speaker / amplifier into the headphone jack as I had done a hundred times before. Terrible static came out of my external speakers. I tried different cables and nothing would fix the static.
The fix I had to use was to put a microphone next to the tiny speakers of the laptop which were working fine. This little trick was enough to save the day.
In fact, this is a handy trick in many situations when you think you are going to be able to hook a tape player or some other audio device into the main sound system, but can't.
It's also handy if it's just not worth the trouble to hook into the main sound system to listen to a brief audio clip.
I'll also remind you that I am a big advocate of handheld microphones. Being able to either hold or lay a microphone closeto a speaker is yet another reason I like them. This trick would be a real hassle with a clip on microphone.