Podcasts
I've always been an advocate of audiobooks, because they build both my knowledge and auditory skills in a meditative way that helps start my morning or pass my free time. However, they cost money.
So, I've begun listening to podcasts as an alternative. Specifically, I listen to Tim Ferriss's podcast as he brings in neat speakers (e.g. Chris Sacca, Arnold Schwarzenegger) and discusses content that's directly applicable to everyday life, ranging from time management and better sleep to entrepreneurial and relationship advice.
Podcasts are a huge win for me, and I can't wait to further explore the vast library of them. I highly recommend these if you love learning from professionals in various fields of expertise.
Swimming
I'm not sure why I didn't start swimming sooner. Maybe it's because swimming isn't really what competitive baseball players or weightlifters do. However, since I've started swimming, my performance in the gym has increased tremendously, and I feel substantially better both mentally and physically. I feel calmer, my meditations are more focused, and my breathing has improved.
If you're a weightlifter—competitive or casual—I highly recommend introducing some sort of cardio into your program. I know your bro-friends may tell you that cardio is for wimps, or whatever it may be, but that's a load of nonsense. Cardio will significantly improve your blood flow and endurance, leading to better pumps, less fatigue during your reps, and faster recovery in-between your sets. Swimming is my cardio of choice because it produces no joint pain whatsoever. If you're curious, here is my powerlifting routine.
Deadlifted 540 lbs for a personal record weighing 179 lbs at my first USA Powerlifting meet. Prepared with intense swimming and lifting.
Udacity
I highly recommend looking into Udacity's programs if you're interested in designing and implementing neat computer science projects that are directly applicable to the industry or your entrepreneurial endeavors.
Their lectures are clear, the assignments are intriguing, and the teachers all have extremely credible backgrounds. I am currently enrolled in their iOS Development program, and I actually find myself looking forward to lecture which is rare as I've always been more of a self-learner. Udacity does a phenomenal job of teaching while still fostering an independent mindset by encouraging creative solutions. I highly recommend checking out their website and reading about their programs here.