To Lie, To Lay or To Lie?

Infinitive	Simple Past	Past Participle	Progressive
1) to lie	lay	lain	lying
2) to lay	laid	laid	laying
3) to lie	lied	lied	lying

1) To Lie - to put oneself on a horizontal position; to rest in a horizontal or flat position. It doesn't have an object. It's an intransitive verb.
If you lie in the sun too long you'll get a sun-stroke instead of tan.

2) To Lay - to put down in a certain position; to place in proper position. It always has an object. It's a transitive verb.
I can't remember where I laid my hat.

Note
The verb to lie can express involuntary actions whereas the verb to lay can't.
The carpet has been lying at the door.
She has been laying her head on his shoulder for ten minutes.

3) To Lie - to speak falsely; to tell lies.
People who lie are never corageous.