Tired of building web applications? Trying maybe C++?
If you're just starting out in C++, I recommend starting with some simple console-based applications first. Get used to the syntax and some fundamentals like strong typing, pointers, and understanding the difference between pointers and references. (Depending on your experience as a developer, you may already know all or most of the theory behind these concepts.)
If you're comfortable with these things, building GUI applications is easier (although still far from trivial.) I'd recommend going with a toolkit like Qt rather than MFC, which is largely deprecated in favor of dot NET, if I'm not mistaken.
Edit: also, consider trying out a language like C# instead. C# is newer, a little more cohesive, and lets you use dot NET for building Windows GUI applications.
My latest interest is in Robotics. You can get a microcontroller for about $30 (arduino.cc) - and miscellaneous motors off of E-bay. I also have some cheap rangefinders and a GPS receiver - each of them under $30...
I build web apps as well. I'm not really tired of it, but I spend all my spare time programming in C.
Write a game. An action game. Like, a shoot-them up for example.
You'll discover the other face of programming. Use whatever you want to make it. C++ is a good choice, but any language will be good. C++ will be harder to "master" than other languages but learning it will make you understand a lot about other languages. But that's your choice : the project domain is more important than the language (that is just the tool).
Just try to make a game, I think it will really be different and you'll discover a lot of interesting things. I recommand a shoot them up because it's visual, make you learn basic graphic rendering, basic collision management and is a good base for a potentially interesting game (if you add a feature that makes it stand appart) that will keep your motivations for learning.
Look into mobile application development like on Android or iphone. C/C++ will come in handy.
Buy "The C Programming Language" by Kernighan and Ritchie and work through it.
Ideally, you also have access to an OSX/Linux system and can work on that. (C and Unix go hand in hand).
C++ is great and all, but writing GUIs in MFC is just stupidly painfully compared to any other reasonable framework out there, like .NET (VB, C#, C++/CLI, pick your language) or Cocoa/Obj-C on the Mac OS X / iPhone OS. Qt is probably better than MFC.
If you're used to working in relatively high-level languages such as C# or PHP, going back to something like C++ where you need to do your own memory allocation and other low-level stuff will probably seem cumbersome. Personally, I was happier making the switch in the other direction, and having much more done for me.
But if you do want a challenge, C++ could be a good option. Or, go straight to embedded. Robotics is a very fun topic, try to fit interesting things (that really move!) inside the 2-KB RAM environment of a PIC microcontroller :-)
I would recommend trying to implement something useful in C/C++. Is these a utility in your operating system you don't like? That you think you could improve? Have you always wanted to do X easily and have a good idea? No matter how big it might seem, research it. Learning an OSes API will teach you a lot about C/C++. Add a user interface in the library of your choice to learn even more. Basically, push the envelope a bit - building a calculator is great or a little console app for learning a few things, but building a fully fledged app with a purpose will really teach you things.
Add intelligence to a simple game using a neural network. I've always wanted to add a neural net to Oware to see if it improves its wins.
If your into pain, you could correct flaws on Windows Vista and 7. :-(
I'd recommend moving to Python rather than C++ if you're coming from a web design background. Get good at object-oriented programming, encapsulation, and related things before you go to C++ and have to deal with pointers and cleaning up after yourself.