Does anyone know what language or platform is used to develop apps for Google+?
I'm hoping Python, but I know google has a lot of other mediums they could use for this. I'm fine with hearsay as I know the game portion of google+ is pretty new.
App development for Google+ looks to be similar to app development for Facebook. That is to say, you will likely be able to use any language or platform that allows the game to be played in a browser, and you will interface with the API via RESTful style requests (basically making an HTTP call to something like api.plus.google.com)
Purely speculation here but...
The Google App Engine supports Python, Java and Go for site development. It wouldn't be unreasonable to suggest Google will give all three GAE languages the right hooks for Google+ application development.
My current approach is to use GAE and Users Python API, since to use a Google+ app you will have to authenticate with a Google account.