How can I clone an SQL Server database?

You could try to detach the database, copy the files to new names at a command prompt, then attach both DBs.

In SQL:

USE master;
GO 
EXEC sp_detach_db
    @dbname = N'OriginalDB';
GO

At Command prompt (I've simplified the file paths for the sake of this example):

copy c:\OriginalDB.mdf c:\NewDB.mdf
copy c:\OriginalDB.ldf c:\NewDB.ldf

In SQL again:

USE master;
GO
CREATE DATABASE OriginalDB
    ON (FILENAME = 'C:\OriginalDB.mdf'),
       (FILENAME = 'C:\OriginalDB.ldf')
    FOR ATTACH;
GO
CREATE DATABASE NewDB
    ON (FILENAME = 'C:\NewDB.mdf'),
       (FILENAME = 'C:\NewDB.ldf')
    FOR ATTACH;
GO