If you're going to CPAC (Conservative Political Action Conference) and you don't want John McCain to be the nominee, the best way to achieve your goal is to ask McCain a tough question that will make him look very bad, and then upload the videotape of his response to Youtube and other video sharing sites. When uploading, use a catchy title and a detailed description, and promote it through Digg, blogs, etc.
And, even if you aren't going, you can still help by contacting those attendees (such as the list of those on "Blogger's Row" here) and urging them to ask tough questions.
I suggest concentrating on just two questions: this one, and even better this one. In any case, it's important that the questions you ask are questions and not simply rants. It's also important to try to anticipate the response and change the question to make a scripted response more difficult. More tips on asking questions here.
Here's the video for the best topic to ask him about:
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