If you play League, you'll see how they advertise various events etc not only on the client login screen, but also the client main screen.

Maybe implement some small banner section of the client for events, or perhaps the whole screen could be taken up with a splash. This would of course be on the initial menu screen.

This would really bring about a boost to user interest not only in organized events, but also would also attract users who might have never even considered that toribash had forums, to the forums. This would boost community activity which means more people for events, yadda
dadda
yadda.