[newbie] extracting programs from tar files

[Doug Ransom]

I frequently find I want to install some package (typically a program of 
some sort, most often a python library).

They usually come as tar files. Before I unpack these files, is there a 
place I should locate them in the file system? 

Some programs have a setup.py, some just have a couple python files in 
them.  I am not sure how to proceed in getting stuff set up correctly.  
For things that have a setup, I can run setup fine.  For things that are 
just a couple python files, what should I do?

Doug Ransom