A user with total control permission accidentally deleted the site he was working on. This site doesn't appear on the user's thrash bin or deleted from it. How can it be recovered without resorting to a collection site backup?
@PirateEric already covered this in his reply to @C. Marius, but I'll try to provide a little more detail for you on it.
If you're running WSS v3, you won't be able to recover the site from a recycle bin unless you've installed the free Site Recycle Bin add-on for SharePoint 2007 that was released a while back by MSIT (more info on it is available here: https://governance.codeplex.com/wikipage?title=SharePoint Site Recycle Bin)
SharePoint's end user-facing recycle bins only will protect deleted documents and other items, or libraries and other types of lists; they do not capture deleted sites or subsites. With Service Pack 1 for SharePoint 2010 (both the Foundation and Server versions), they built the Site Recycle Bin into the product, but even then it has to be enabled by an administrator in order to be in place to protect deleted sites or subsites.
If you don't have that tool installed, you're going to have to restore a backup of the content database that contained the deleted site to a separate recovery farm and extract it from the recovery farm with Export/Import as C. Marius has already stated.
Did you checked the 2nd-level Recycle bin (at the site collection level)?
Nevertheless the restore from a backup is the way to go either via a Site Collection restore or Database Re-attach to a temporary farm, followed by stsadm - export /-import of the particular sub-site only.
The result is easy to restore in your actual farm.
Hope it helps, C:\Marius