SQLTuples is a FREE product that adds a number of tuple types and constructor functions within the T-SQL scripting environment that can be used anywhere that a compound type is needed.
Tuples of between 2 and 6 elements can be constructed easily using the supplied constructor functions. Tuple elements can be of any standard type, and different types can be freely mixed within a tuple.
SQLTuples was originally created in order to allow the creation of aggregate functions in SQL2005 that accept multiple input values. SQL2005 aggregate functions normally only allow one input value, but there's not reason that can't be of a compound type - so you can simply bundle the input arguments together using a nested tuple constructor function as the input argument to the aggregate.
For users for SQL2008 and above this is not needed, but there are still plenty of situations in which tightly-coupled compound values may be an advantage (e.g. coupling monetary values with currency codes).