I'm going to assume you're asking about frameworks as well since comparing PHP to CGI Python or CGI Ruby wouldn't exactly be fair (even though
some people love to compare Rails/Django to pure PHP). This isn't a straightforward question, so I'm not going to give you a straightforward answer, but here goes.
Based on my experience of working with Rails, Django, Pylons, Zend, etc. I'm going to have to say, "It depends LOL!1!". If you're on completely level playing field with Ruby, Python and PHP I would say jumping into Rails would be a good choice since there's so much quality training material out there (and it's a really good framework if you can ignore the fan-boys).
Since you mentioned some real time stuff you might want to look into something like Tornado/Python (tornadoweb.org) though I honestly can't say if any other framework would prevent you from real-time since I don't know anything about your server/load.
If you don't know what MVC is, or think Models are skinny european women then I'd almost be tempted to say play with some PHP without a framework for a little while. This will let you get more familiar with processing a web form for example, or uploading an image without a framework telling you how they think it should be done. Get your hands dirty in other words.
I dunno, that's just my advice. Hopefully I didn't dumb it down for you but I had to assume you've never built a web app.