Ever notice how the little plastic bag closers at the end of the bread are different colors?
These colors often(though not always) indicate the day of the week the bread was baked.
You can remember them alphabetically:
* Blue = Monday
* Green = Tuesday
* Red = Thursday
* White = Friday
* Yellow = Saturday
(I guess they don’t normally bake bread on Wednesdays or Sundays)
Also a nice little graphic lifted from Wisebread.
Note this is not true for all bread types. If you always buy the same type of bread it may make sense to call up the bakery to ask.
Sources:
http://www.snopes.com/food/prepare/breadtag.asp
http://www.wisebread.com/breaking-the-bread-code-how-to-get-the-freshest-loaf