It's my dream that, one day, the browser-side code and webserver-side code will be 1) written in the same language, 2) be able to communicate as peers, via IPC mechanisms, and 3) that the language and/or framework explcitely include distributed computing features, to make it easier for the programmer to traverse the process barrier (or possibly even make the barrier invisible).

Possible candidates for this:

Broader ideas along these lines: