Once again, I'm not sure if this has been posted, although as far as I know this is an original idea:

A friend of mine told me that there was a technique that her friend used to have lucid dreams at will. It was very simple. Before bed, all he would do is think to himself "There is going to be a lion (or some other odd object in his dream) and when I see the lion, I will recognize that sign and become lucid." He would then think about this lion for awhile and then go to sleep. When he dreamed, he would notice the lion (or whatever object) and become lucid.

any thoughts?