In keeping with @Robusto's comment on opening a can of cat food, the most reliable way to get our recalcitrant kitteh to return to the house is to say the cat's name (or a familiar diminutive thereof), followed with "cheese!" in a high-pitched voice. Kitties seem to love high-pitched voices mentioning food. The "cheese" vocalization is in fact an offer of food -- sometimes literally a tiny piece of cheese, sometimes actual "cat food". Imagine a trained dolphin receiving a fish after performing a trick, and you will have imagined a situation which is not completely unlike this one. This trick also works for our other cat who was not brought up with cheese as either an offer or a reward. I think it's the high-pitched voice, with the likely reward of food that does it.