Learned this neat trick today.  This obviously is not well-known.  I've been dealing with SQL for many years and haven't heard of this till today.

MSDN article on SET FMTONLY

One very useful application of this trick is to get the schema of result set returned by the stored procedure.  More interesting scenario is when your stored procedure has more than one result set it returns depending on the logic inside of your stored procedure.  If you use this setting against such stored procedure, it will return the schema of all possible result sets.  Instead of executing the query, query is compiled to get schema of result sets.

Neat.