Thanks for yet another helpful and informative response.
You can plug as much stuff into your PSU as you want, but if you don't plug it into your mobo it's not gonna turn on. If you want to make it turn on without the motherboard you can do like what CrazeD was showing us, but be warned that it may be bad for the power supply to run it without enough load on it. If you decide to do this to make sure it works I wouldn't recommend leaving it on for very long. Some people say it won't hurt it, but I say better safe than sorry.