So, RoR vs ASP.net MVC?

Recently i have been trying all kinds of fun stuff, for instance yesterday i spent a few math classes and most of my spare time, playing with C++.

But i have always wanted to master a technology for building websites. Sadly, asp.net web forms is a black art which is just not trivial, as i see it.

So i have surfed the internet and found RoR and ASP.net MVC/Monorails.

I like VB.net, but Ruby does seem kinda cool. It could be cool to learn.

Im already fluent in VB.net and C#, som im thinking it would be good to learn ruby, so i learn a dynamic language too.

But the power of the .NET framework would be tough to live without.

So im wondering, should i learn Ruby(On rails) or should i do ASP.net MVC OR Monorails?