Bruce Banner versus Clark Kent, WHO YA GOT?!
Granted, DC's big blue boyscout and Marvel's second most lovable freakish behemoth -- sorry Bruce, but Ben Grimm just seems like he'd be more fun to have a beer with -- have squared off before, but this is the first time the two have battled it out in real-time.
Also granted, this being a fan-made CGI film odds are pretty solid that it butts up against a whole slew of intellectual property violations, but since creator "mhabjan" isn't making a dime off of this thing (as far as I can tell, this was created as a class project), he hasn't seen a C&D order from either Marvel or Time Warner.
All that aside, the important thing here is that this video (and its two sequels, which I've embedded below), are surprisingly good. Not just in the big, apocalyptic-clash-type moments either. That sort of thing is a given when you have two fighters who can literally toss mountains around. No, most impressive are the subtle moments. The way Supes lands, the emotion on Hulk's face, stuff like that.
Plus, this is something you will never, ever see in a major Hollywood production thanks to all those aforementioned IP issues, so fans of the two characters should be giddy to see it realized in such a solid form. It may not be perfect, but it's a pretty cool couple minutes while it lasts.