At first, I thought it was a question about the syntax introduced in SQL 2008 that allows you to insert multiple records with a single insert statement, like so:
Insert Into @Foo
(This syntax gives the same result that a 'UNION ALL' insert statement would.)
But, when none of the answers seemed to fit my initial theory, I took a closer look and saw what was going on.
Great question...exactly the right amount of trickiness to make you take a hard look at things!