It’s a date (field)

Following a discussion I just couldn’t stop myself participating in about date form fields on the list I googled a bit on the topic of date entry usability and found a extensive usability study on hotel booking systems.
There is no silver bullet, and it is very dependent on the product. The battling sides are making it easy to use for the vistors vs. stopping them from entering wrong data. As a rule of thumb I found for our projects:

• Free text entry fields with attached popup calendars work best.
• Three dropdowns work well when the date range is very limited