Injecting large amounts of random data


Can anyone recommend a good way of injecting large amounts of random data into tables?

I’d like to generate a mixed variation of data and be able to insert 1million+ rows into a number of tables to test performance and stability, as well as test a few applications I’ve been working with.

I’m hoping there’s an application already developed to accomplish this so I don’t have to conjure up a script of my own.