By default SQL Server 2005 and 2008 Management Studio will save whatever you are working on every 5 minutes or so into your \Documents and Settings\username\My Documents\SQL Server Management Studio\Backup Files\ dir.
This has saved me time on multiple occassions.
There is no way to turn this feature off in SSMS but you can control it by changing the following registry settings where 1 is enabled and 0 is disabled.
[HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server\90\Tools\Shell\General\AutoRecover]
"AutoRecover Always Enabled"=dword:00000000
"AutoRecover Enabled"=dword:00000000
