The most useful 3rd party Strava add-on sites?

deadhead1971

Strava - love it or hate it, it's had big impact on cycling over the last few years.

There's a growing number of sites that can do weird and wonderful things with Strava data (through the Strava api) and I've made a resource to list them all.
You can submit new ones too.

http://www.scarletfire.co.uk/strava-sites



Any good ones that I've missed?