ARGHH! I want to post something interesting! I really do. I am not worthy of this thread.
Well, the standard 5 string banjo has 22 frets and can be easily tuned by ear by fretting the behind the 3rd fret on the second string, playing it, followed by playing the open 1st string below it. These should sound the same if tuned properly, and should be in the key of D. Then you can fret behind the 4th fret on the 3rd string, and play the open second string below. Again, these should sound the same. And should be in the key of B. Then fret behind the 5th fret on the 4th string, play the open 3rd string. These should sound the same also and be in the key of G. This will leave the 4th string in the key of D when played open. Then, to tune the 5th string, fret behind the 5th fret on the 1st string. And play the open 5th string. They should sound the same and be in the key of G also. It will now be tuned in 'Open G' tuning which is the most common way to tune a 5 string banjo, although there are plenty of other ways.
This is called 'relative tuning' as when you have one string in tune, you will be able to tune the banjo to itself. And you won't have to rely on an outside source.
Relative Tuning of the 5 String Banjo:
Playing all of the strings openly will now produce a G chord. (Probably the easiest chord to ever learn
)
(It musn't be forgotten that the 5th string is the highest pitch, and the 4th is the lowest pitch. This is unique to the banjo and dates back to it's African origins.)
So, now you all know how to tune up your 5 string banjos. 
_________________

THINGS I LIKE
Parasaurolophus, Plesiosaurs, Dinosaurs, Pterosaurs, Music, Tuna, Chocolate milk, Oreos, Blue things
Parasaurolophuscolobus. Parasaurcolobus. Colobusaurolophus.
....And Nunchucks are my friends.