Jombackup, for performing daily mysql backups and emailing them to the address of your choice.

The default settings should be enough to get you up and running, but there are plenty of configuration options available to you, including modifying the text of the email sent to you, changing the default email address and the actual type of mysql data backed up. Literally you should be able to fire and forget.
This mambot is designed to allow those people who do not have access to, or are unwilling to use, Cron, to enable daily backups of their Joomla mysql data. It runs every time Joomla is run. Most of the time, all it will do is check for the existance of a checkfile with today's date. If the file exists it will not do anything else, however if the file doesn't exist (IE the local server's time has passed the midnight hour and this is the first time today the site has been visited) then the plugin will perform a backup of the system's mysql data and email it to either the system default email address, or another that you may have specified in the config.

Very important: Pay attention to the Notes regarding the Testing option. I kid you not when I say that you could bring a server down if you abuse this.
Installation: Administrator->Installers->Mambots. Upload and install the plugin, make sure you visit Mambots->site mambots and click on the link to JomBackup system plugin to edit & publish it.
How long does it take to perform a backup?
The answer as always, is "How long is a piece of string?"
I can only tell you how long it takes to perform a backup on jomres.net. The backup file, uncompressed is appx 33mb, compressed it's about 2mb. It takes jomres.net roughly 20 seconds to perform the backup and email it away.
Please note that this script needs write access to the media directory by default. If you are using safe-mode then you may find that you receive empty emails or that backups are simply not happening.