Move an email into @SaneTomorrow, and SaneBox will pop it back into your Inbox tomorrow morning! Between now and then, it will disappear from your Inbox and only appear in the @SaneTomorrow folder. This is a great tool for uncluttering your Inbox if you don't need the email until tomorrow.
To turn on this feature, or to hide it if you do not wish to see it in your folders, go to your Settings page. Under Folders you use, click Show or Hide next to @SaneTomorrow.