What week is my rMBP?

[insimbi]

I've seen various posts indicating what week their MBP was built or manufactured. How can I tell from my serial number the week or month it was built?

 

[elpmas]

coconut battery should show wouldn't it?

 

[simsaladimbamba]

www.appleserialnumberinfo.com might help, in addition to the already mentioned banana.