In ScriptSharp I like to store data browserside with WebSQL. Unfortunately WebSQL (http://www.w3.org/TR/webdatabase/) is discontinued in favour of IndexedDB (http://www.w3.org/TR/IndexedDB/).
Now I'd really like to see IndexedDB implemented in ScriptSharp. It's becoming mainstream now: http://caniuse.com/#feat=indexeddb
It's not as fancy as IndexDb but there is already support for Local Storage (http://caniuse.com/#feat=namevalue-storage).
You access it through Window.LocalStorage.GetItem or Window.LocalStorage.SetItem.
Yep, its certainly interesting ... if you're up for getting it started and filling in the missing types in Script.Web.dll, that would be awesome.
Okay I have implemented the asynchronous API. Sent pull request #319.