This very rarely EXACTLY guesses your age, but normally it gets quite close (always within 9 years according to the tests I did) Wow! 12 views in under 12 hours! Update: I made it more accurate for people with younger parents - but even more random for people with average/older parents.
Feel free to joke about how wildly incorrect this can be - but no complaints - it's almost impossible to make something that guesses your age without you inputting your birthday/year.