Have you encountered the requirement where you want to assign all Even numbered records to one person and all Odd records to another? Here is a simple solution using the workflow rules that can help. You can use this on custom objects or even on objects that do not have Assignment rules. The requirement can also mean assigning the alternate records to two persons. This is similar to Round Robin assignment to two persons using workflow rules.
Lets define the requirement as:
Assign all records of an object that are of even number to “Joe” and odd number records to “Mary”. The odd or even number can come from a custom field “Record Number”.