https://www.youtube.com/watch?v=VZ0aWbZjX6M
https://www.youtube.com/watch?v=eX5hUdhI4Hs
https://vine.co/v/MpXia7EmwAl
https://dl.dropboxusercontent.com/spa/9hdhy0x8uk9d155/02uwwr...
https://dl.dropboxusercontent.com/spa/9hdhy0x8uk9d155/iwy2qc...
It does run both in Safari and WebView and it's pretty fast:
http://blog.ludei.com/webgl-ios-8-safari-webview/
http://www.photonstorm.com/html5/a-first-look-at-what-ios8-m...
It has very decent subset of features supported:
https://www.dropbox.com/s/i80qxzap59i230n/2014-06-02%2023.43...
But apparently it's not yet fully stable.
Also Dean Jackson from Apple's WebGL team tweeted, please direct eventual bug reports to him:
https://twitter.com/grorgwork/status/473580744892112897