Auditing specific database events
SQL Server 2008 (r1) introduced Extended Events and with that came SQL Server Audit and works similar to XEvents to audit events. So it is less intrusive than C2 Auditing and server side traces.

It is very granular and fairly easy to setup. This feature is available in all editions of SQL Server 2008 R2. A good write-up intro/how-to can be found here by Brad McGehee. Thomas LaRock also did a great article on Simple-Talk walking through creating/setting up the audit.

Reading through the articles mentioned above you will note that you can have the events logged to different places (windows app log, file, etc.). From that you can then write PowerShell scripts or T-SQL scripts to alert you of whatever you want. Much more easy than screwing with C2 Audit trace files.