I've been doing Latin since I was in the third grade, now I'm in eighth, so that's six years of learning a language that no one uses in everyday life. o-o (I still stink at it too). And I'm lucky to have a teacher that doesn't take anything seriously so he taught us the phrase "Semper ubi sub ubi", which translates to "Always where under where".
I also know...
Carpe Diem= Seize the day
Usus est magister optimus= Experience is the best teacher
Cogito ergo sum= I think, therefore I am
some other phrases that I can't think of
the apostle's creed
the Lord's prayer
Adeste Fidelas (Christmas hymn)
and probably some other stuff that i can't think of right now.