Multiple sources (for example, here) state that Ukranian Parliamentarians routinely have physical fights on the assembly floor. The videos look a bit like stage fighting to me, however. Are these real fights, or faked? If they're theater, are these real government officials, or actors?
They're real politicians. This is easy enough to prove- the third video in that link has Oleh Lyashko taking part. If you do a Google Image search, you can see his face and you get a clear look in the video (as shown below), so it definitely is him.
It seems a bit silly to suggest it's theatre, though. Why would politicians engage in anything other than politics, especially when it seems to be quite a cut-throat enterprise in Ukraine? I'd suggest that they do it because it's a part of their culture.
In fact, BBC News have an article on this very topic.
If it helps, I can give more examples:
You get the idea. Yes, they do have regular fist fights, and you can see lots of videos online to attest to that.
Addendum: Compro01's comment link is good enough to be worth inclusion. This is actually covered in Wikipedia- not only that, but many other nations have their own incidents.