Lips

A quick solution that requires a turbo controller ...

I bought "Ice Ice Baby" from the marketplace (160 points), and used my turbo controller with the A-button taped down to continuously select that song. It also continuously plays tambourine throughout the song, which sometimes helps get the "Great Party" medal.

NOTE: I have only tested this on the three expansions, I don't know if that will work on the original Lips game. You can gather medals with any of them, but the achievement for 1500 will actually only unlock in PartyClassics or LoveThe80s. For the 1000 achievement, you can use any of the expansions. Anyway ...

Using a keyboard, I recorded a rapid succession of high-pitched piano notes, and then looped it with a piece of audio software, creating a ten minute MP3. Here it is: http://www.mediafire.com/?b2wnnrr3aoqke7z

I played this MP3 (on repeat) LOUDLY through some headphones, with a wired USB mic resting against one of the phones, picking up the sound.

This got me a full-combo on the song, and five out of six medals (everything except "Great Performance"). Sometimes it would only be four, as the "Great Party" medal sometimes didn't trigger, for whatever reason.

But the upshot is that leaving this set-up running overnight, I woke up to about 600 medals more than I had when I went to bed.

If you don't have "I Love The 80s" or "Party Classics", you have to use the wireless mics, which will probably run out of batteries at some point, so you'll need to replace them once or twice.

Also, if that download link expires, you might be able to get away with just playing some music through the microphone, so long as it's something that isn't just a constant tone. The effectiveness of what you play is determined by how "staccato" the sound is, so you might find you only get 2-3 medals per song, or something, but it's better than nothing.