Disclaimer - Use these scripts at your own risk.  I recommend executing them against a test database to verify that they function properly before using them against a production instance.  If these scripts do not work as intended, contact me.  You are welcome to send me your scripts also and I will post them here, giving you full credit, if I find them useful.

as_new.sql - Displays information on currently active non-background database sessions
apps_job_id_to_session_id.sql - Allows you to trace an E-Business job to a database session.  Handy for troubleshooting long-running concurrent jobs.
sql_hc.sql - Based on the Oracle Support SQL health check script, this script first identifies the longest-running query, then performs a detailed analysis of it.
blocking_sessions_new.sql - Identifies blocking sessions in RAC and non-RAC environments
apps_patch_level_query - Displays the application short name, the application name, and the patch level of an Oracle Applications instance.
blockers_and_waiters - A handy script that lists sessions (sid,process,code,etc.) that are either blocking other sessions with locks or have locks that are possibly causing other types of waits.
  db_total_size - Displays the allocated space, actual space consumed, and difference in MB and percentage.
sql_server_health_check_v1.sql -   SQL Server health check - initial review of SQL Server DB
  lock_info_complete - Complete locking information including lock type being held

  lock_info_quick -

More simplistic object locking information using V$ACCESS view
rman_level0_backup.sh - Script to perform RMAN level 0 incremental backups.  Includes checks for RMAN sessions already running and block corruption.
rman_level1_backup.sh - Script to perform RMAN level 1 incremental backups.  Includes checks for RMAN sessions already running and block corruption.
  role_reverse_engineer - Creates SQL necessary to reverse engineer non-default roles from an existing database
  string_search - Searches a database or schema (char, varchar2 columns) for a given string. Revised to include CLOB and NCLOB data types.
  tablespace_report - Lists tablespaces, datafiles composing them, free space, and total space in MB's
  tablespace_report_html - Same as tablespace_report, but generates its output as an HTML file (Oracle9i / SQL*Plus only)
  userclone - Generates a SQL script based on user input to create a user mirrored from an existing user.