What got me interested in C was microcontrollers. The Arduino and like boards are Atmel ATMEGA processors that can be programmed with GCC. It was more compelling to watch some real I/O than to put together console apps. The boards are typically around $20 and can be found at lots of sites.

Cool demo: Blinking LED

Data Structures: An Advanced Approach using C is also a very good book for data structures.

The Linux kernel is a great project in C.

I recommend K&R and Head First C, nice books. And practice, practice, practice

C is a key language, if you want to understand memory management and resource handling it's the way to go. K&R book is still a good resource, I wouldn't go after another book before finishing it.

C is a very basic language in terms of syntax, there's almost no complexity if compare to languages like Clojure, Haskell, Lisp or Scala, but on the other side is a wider world, you can do a lot of stuff with many potential solutions and the only way to handle them is to try. C, more than other languages, requires a lot of time to code and try different solutions, mainly when asynchronous computation is introduced. Keep going!

What is almost everyone trouble with old C? The language is older than the grandparents of a few of the ones present here. Did it age that bad?

K&R C is the best book for learning C.

Modern publications will not provide you with more knowledge, but they will have "did you know?" text filling the margins, which is distracting.

I'm not a C programmer, but it is the language I was introduced to when first learning how to code. Writing small programs in C made it clear to me how code is represented in memory. You're certainly on the right path.

I'm a fan of Modern C. It's free, extremely precise in its language, and covers all the latest language features.

C is not difficult to learn, so don't sweat it. Especially if it's not your first programming language (even if it's your first type-safe language). Get good at the simple stuff like fast arithmetic, memory bookkeeping and debugging, then dive into either the Python C API or C++14 (why not both?).

Seriously, go to your local community college and sign up for their C class. You could learn it by yourself, and a lot of people here are going to give you some solid advice about doing that. Having access to a professor and a lab full of peers learning the same thing as you is a valuable resource.

If you are already comfortable with other languages, like Python, C shouldn't be much of a problem, language wise.

Learning C is 10% learning the language and 90% learning how to use the tools. Here's what you REALLY need to focus on:

1. Learn the tools. Specifically, the gcc tool chain. Specifically the debugger. Learn how to use these tools without an IDE.

2. Pointers are a bitch, but they are useful. Unlike Pyhon, you need to actually know how pointers work in C.

3. Learn how to safely allocate and deallocate memory.

4. Datastructures. Walls and Mirrors (book) is a good resource. But you should probably also take a class for this for guidance.

Also, take the "self teaching" advice everyone else is giving here. It too is valid.

you actually need to do the K&R exercises on a "modern" compiler. Have fun.