The judge lay down for a nap, then she got up and laid down the law. Or did she?
The judge did both correctly—grammatically, at least. Here's the whole story:
Wrong: She laid down on the shag carpet. Right: She lay down on the shag carpet. Wrong: Mom lays down for ten minutes every day after work. Right: Mom lies down for ten minutes every day after work. Right: He just wanted to get laid. (It's the idiom, so it’s OK.) Summary of forms: recline (intransitive): lie, lay, lain place (transitive): lay, laid, laid falsify (intransitive): lie, lied, lied