Probably, the biggest annoyance of downloading files from usenet is the check with QuickPar to verify the consistency of the downloaded files. After waiting a long time (repairing can take hours!), you also have to unrar the files.
ParNRar is to automatically par and unrar files in a specified folder. Par-N-Rar repairs RAR-files, when in company of PAR-files. Once all files are (repaired and) veriified, it unRARs them. Once it finishes unRARing a RAR archive, it’s an option to delete the RAR automatically.
Download ParNRar here, or go the the project page