They take awhile to mature, and it is getting late in the year. Maybe if you live in SoCal.

Kristen, fireduck makes a good point, it is late in the season, but I live in Tn. and my Winter Squash is still setting fruit. So depending on where you live, while you may not be able to start an entire new plant, you can hand-pollinate the existing vine. It's usually done by bees and insects of course, but if you don't have many flowers around, sometimes places can be short enough bees. Hand-pollination is even done when many bees are present, just to ensure higher yields.

To hand-pollinate, check your vines each morning for flowers. If there is a female flower present (the female flowers are directly on top of a tiny fruit,) you cut a male flower off, leaving some of the stem attached to use as a handle (the male is a single flower growing on a tall stem,) peal back the petals, and expose the pollen-covered stamen. You take the male flower, and gently rub the pollen onto the pistil of the female. It's very easy. Be careful if you try to maneuver the female flower, they can be very fragile and snap off.