I wrote a client side speed test.
Shame that is how most of the internet is, given the super-servers are bandwidth bogged 24/7 and most personal home pages are on shared hosting, etc.
In summation, this is a more humble and honest speed test than those that do multiple (Pingback?) links to a server dedicated to doing so.
I don't even want to run multiple times to get an average, so you can get a feel for just how unstable your internet speed really is.
Web app in link ^ or in iframe v