See BillWakeTestFirstChallenge.
Truth be told, this isn't even a ProtoPattern, it's just an idea sparked by the BillWakeTestFirstChallenge.
A great way to get people involved in something new is to demonstrate how it's done, why it works, and what the benefits are. Hands-on is preferable.
Therefore,
Run a TestFirst challenge among a few of your colleagues to get them familiar with the concept of having tests before they code. This will help them realize the benefits of having tests.
Then,
Start using tests on real projects to demonstrate that coming up with the tests in the first place isn't really that hard.
Discussion
Of course, BillWake's great source material is the obvious place to start.