I have an Event page, to which a viewer can have many possible responses (not mutually exclusive): accept, decline, nominate someone, propose a new time line, thinking about it, email host etc.

I think putting a lot of buttons at the bottom of the page make the page very cluttered. What should I do in this situation?

I am thinking of creating a left-side bar with multiple buttons. But this is a little bit unorthodox. What are my options and what would be popular solution for this situation?

Below is a sketch for my event page. (Sorry I don't have enough reputation to upload images yet).

______________________________________________[Account][Setting][Nav_bar_items]

[Left side bar       ]          Event
[Accept                ]          location: Starbucks
[Decline                ]
[Send a message ]          Time: 10 AM Sunday, Nov 11, 2011
[Change time        ]          Duration: 20'
[Change location   ]
[Refer someone     ]
[Change channel    ]