This fails on VS2010 RC LINQ-to-SQL with the InvalidOperationException "Stored procedures cannot be used inside queries.":
var foo = (from a in aTable
from b in this.SomeStoredProcedure()
where a.Id == b.Id
select b.Id);
SomeStoredProcedure is a SQL procedure which returns a table. 'join' also appears to fail. Any thoughts why?