Today I've noticed that our frontpage was taking more than 10 seconds to load. Which is by any means unacceptable. I fired up Firebug and had a look at the network tab. Everything seemed normal, except for the response from the server. The server was taking 10s to generate the first response. After that in just few ms all Javascript and CSS resources were loaded. Due to the fact that we haven't changed anything on the site lately & we also didn't have any traffic spikes what I immediately did was submit a ticket with our hosting provider.
In my ticket I explained what the problem was: "The frontpage is loading really slow, it takes more than 10s for it to load. Sub-pages seems to behave way better at around 2s.... Any ideas what could be wrong?"