How to add "date" type custom option for products and make it work?

 Many Magento users, like my company, have similar requirements to let customers choose date through pop-up calendar in the product view page. But Magento merely offer 2 groups of input type, “Text” and “Select”, in Catelog→Manage Products→Custom Options page by default. Is there any possibility for us to add the support for “Date” or “Date Time” input types?

http://www.magentocommerce.com/wiki/4_-_themes_and_template_customization/catalog/how_to_add