Lebuzz.info is a popular French website powered by WordPress, running on a dedicated server that kept hitting its limit during the Royal Wedding (April, 2011) and was brought down often due to huge popularity of the event and this site's live coverage at that time.
My first responsibility was to work with the site's backend, and then with the webhost to make sure the site was alive for the next 48+ hours without any downtime. Once this was addressed, the next step was to optimize the site's load time from being slow to normal, if not faster. Both issues were promptly taken care of and the site's reputation was maintained during and after that mega event.
A complete optimization requires both backend optimization and front-end optimization. I can provide solutions to both. There are some easier and simple solutions with complex performance issues and then there are not-so-easy and time-consuming solutions to some simple speed related issues. One size doesn't fit all. Feel free to contact me for a discussion on your site's particular use case!