Replying to Endurance Athletes

There comes a point where I think a lot of people want to do something they think is crazy but they psych themselves out. With that in mind I've decided that I'm going for a half iron man next summer. I've never done a triathlon before, ran a half marathon or so much as swam a mile but I want to test myself and my resolve. I've recently committed myself to building up both my mental and physical health after years of neglect. So NSers has anybody done anything similar. What crazy feats have you guys set out to do?