Wow, ATOT has spoken. Sounds like it's not such a great plan. I'm rethinking some of my ideas. I see that a bunch of you were wondering where I'm coming from with these ideas. You are correct in guessing that I have never attended a wedding before, so I don't quite know what to expect. While I've been named best man, I have not been told that I'll need to fill any of the roles that were listed in the above post. The wedding is going to be fairly simple--I'm guessing costs to be at $3000-$5000. The ceremony will be held outdoors, and everyone will move inside to a rented lodge for the reception. I don't know if there's going to be a toast, speech, etc--I'm going to have to be prepared for it at any rate.
As to it "ruining" THE day of their lives: If I'm a bit subtle, I know the groom isn't going to care too much. A few weeks ago he asked me if I was aware of any plans for disturbances, and said he was expecting them, it wasn't a big deal, but he just didn't want anyone touching his car, as he's worried about the paint. Of course, he would have been content to elope to the JP, but the bride wanted her wedding.
I still plan to try a few things, depending on how it looks. I'm expecting it to be semi-formal, with an easy-going crowd. Minor disturbances won't concern them too much I don't think, and it certainly won't "ruin" it for them. I'll have to see how things look once it gets going, though -- Sounds like it might not be such a great idea after all.
Thanks for the input everyone!