Earlier today, Microsoft pushed an update to the Xbox 360 Dashboard through its Live service. The update takes, in total, about a minute. The version number of the Dashboard has been updated to 2.0.2255.0.

 Some speculated that this update would include the ability to download content from Xbox Live Marketplace in the background, so you would not have to watch the download meter slowly tick up. Unfortunately this feature is not included in this update, but according to Xbox.com, here is what is:

 – Improvements to the Xbox Guide.
 – Option to retain your saved games when you delete a profile.
 – Increased accuracy of "last time played."
 – Network configuration improvements for Xbox Live members in the Netherlands.
 – More detailed messaging for unreadable disk or region errors.

Of course the update is free to all Xbox Live members, both Silver and Gold. 

News source: Xbox.com 
News source: Major Nelson