I'm no expert on CPU so feel free to disregard everything I say...
In the interest of lightening up your site a little I think that loading 12 videos a header image and ads might use a lot of CPU! The Vimoe vids took about 60 seconds to fully load.
Also, I think that the Gravatar plugin is redundant now that you have 2.7.1 and can I ask why you are even using WP Super Cache? Doesn't seem really worthwhile unless you are getting a tonne of traffic.
My philosophy is that less is more unless more facilitates less.
I'd get rid of those two plugins and have your page length for starters. I'm not sure if it's legal but you could also try downloading and posting the videos instead of imbedding them.
Like I said though, I really don't know anything about your problem.