Instead of pictures, I thought I would share this information from Horticulture On-line:
The biggest mistake people make when trying to ripen green tomatoes is placing them on a windowsill. The light shinning on the fruit will actually cause the skins of the tomatoes to become tough. A better way to ripen green tomatoes is to place them in a paper bag, wrap individually in newspaper or set them in any other enclosed space, such as a cardboard box. By doing this, your tomatoes will keep warm as well as release a gas called ethylene—which is often used by commercial growers to produce a more successful yield. The warmth and the gas will help to speed up the ripening process.
It was not uncommon to eat a garden tomato in January!