There are plenty of sites which offer such scripts (including this one), I've listed a few below:

www.dbasupport.com
www.dbaclick.com
www.oracle-base.com

and of course my own

www.ocp-dba.co.uk

It is always a good idea to make sure you read through and try and understand what the script is doing, to make sure you are getting the results you want.

Good luck