I'm betting it's the ad code. When the resources for the adcode aren't working properly (the x10hosting.com/advert stuff), the include will lag like nothing you've ever seen because includes cause the php document to wait. Once the advert stuff 404's or finally finishes processing it continues.
It should be temporary though - every time I've noticed it, it fixed itself within 15 minutes.
I am getting the same issue. my sig takes a while to load up...
the sig doesnt have the ad code on it, only includes on it are the files required to run it.
Warning: include(http://dawnfire.exofire.net/forums/ssi.php?a=news&show=10) [function.include]: failed to open stream: Connection timed out in /home/colferhq/public_html/dawnfire/main.php on line 7
Edit:
Sorry for the double post, but I fixed it by using a local include rather than a http:// include