Our house is old, and has creaks and squeaks and some of the doors like to swing open when we don't want them to.
Today I found a rock, covered it with a small handkerchief and then with a crocheted doilie. It works perfectly. I cannot say this is my own idea, I saw it in an edition of the British Country Living magazine. It is heavy enough to keep the living room door open for cats to enter and exit the hallway. I am very happy with the result.