Remember one important thing, though. Assuming you have looked for a simple command to do this, and found there is no BACKUP TABLE statement, you should be aware there is a reason this simple command has been left out of SQL Server. This is because table level backups can not be supported. If you need to "restore" this "backup", you will have to deal with a lot of data integrity issues with tables that have foreign keys associated with it, whether these keys are only enforced by the application (as so many developers love to think they can do), or by actual SQL Server constraints.
Another thing to think about is having a lot of "backup tables" in your database will get pretty messy pretty quickly. Make sure you drop these tables before everyone forgets what they were for, and no one wants to drop them as they may have become critical for the application to work.