An easy SPA library written in TypeScript. Either use it as a complete SPA framework, or use any of the classes directly (view render, router, view model handler, http client).
One reason more for Typescript! The next version of the open source framework AngularJS will be built using TypeScript. This was announced from the ng-conf at Salt Lake City. The collaboration has been months in the making, according to Microsoft Program Manager Jonathan Turner, in a blog post (last link at the end).
Cool Examples and more: