I was wondering if anyone tried subliminal messages for attaining lucidity, and I don't mean listening to a 10 minute subliminal mp3 during the day, going to bed and sleeping without getting lucid then saying it doesn't work. I mean putting the audio on while sleeping and trying for at least a week every night. Has anyone tested that?

I'm just thinking it might be an extra thing to help with lucidity while we're sleeping, additional to daytime work like awareness and RCs, not much to lose since all you'd have to do it listen to it while falling asleep.
I don't think it's allowed to post links to other LDing sites so I'll just post a quote from world of lucid dreaming, they have an interesting article about subliminal messaging, go read the whole thing if you fancy.

There are an astonishing number of ways to induce lucid dreams. Yet they all have one thing in common: programing the unconscious to recognize the dream state.

When you think about the lucid dream techniques discussed on this site (meditation, self hypnosis, lucid dream incubation, reality checks, dream journaling) that underlying mechanism soon becomes obvious. And another compelling way to tap into it is with subliminal messages.

Like hypnosis, subliminal messages are direct instructions given to the unconscious mind. There is no mental trickery or hocus pocus going on - this is a scientific method; indeed, numerous scientific studies have proven the validity of subliminals.
What do youse think?