That's the easy part (I figured it out last week myself...): a banjo fitting is a tube that ends in a colar.
Basically like a banjo if you remove the leather and make the handle hollow. The banjo fitting on the intake manifold is screwed in with a hollow bolt with hole just below the nut, which allow air to flow from the manifold through the bolt then trough the banjo fitting to tube connected to the banjo fitting.
There's a nice picture of one here:
Kinda cool, isn't it?
[This message has been edited by Webmaster (edited 09-09-1999).]