You'd get a lot more responses in the Egg Laying forum.  As a general rule, we've arbitrarily decided that 30 days is ok.  Beyond that, they become doggie treats.  
 
There are actually a lot of factors to consider, however.  Were they washed?  Washed eggs will not last nearly as long as unwashed.  In fact, you can leave unwashed eggs out of the fridge for a few weeks, and they should still be edible.  Think about it.  A hen doesn't start sitting on her clutch of eggs until she has a dozen or so.  And how long would it take her to do that?  A minimum of 2 weeks, but it could take a month.  And those eggs hatch into baby birds.
I belive someone said that unwashed eggs should be perfectly fine in the fridge for at least 3 months.  Yikes!  But if you're ever in doubt, use the water test.  If it floats, don't eat it.  It should quickly sink to the bottom.
EDIT: Just wanted to mention that we write the date (just the day, actually) that we collected the eggs on each egg.  We occasionally forget to mention that to new customers, and they may say, "Why is there a '27' on my eggs?"  But once we explain it, they really appreciate it.  We tell them they're good for at least a month, so when the next 27th rolls around, they've hopefully consumed the eggs already.