Quick and dirty approach to generate an arbitrary number of rows of test data in two-column table, where one column should not be unique:

 
1> CREATE TABLE
<table_name> (id int,whatever varchar(10))
2> go
1> INSERT
<table_name> VALUES (rand() * 1000000, 'Datarow')
2> go 2560
 

This will insert 2560 rows into the table "table_name" with unique values for the first column.