While there is no question that enjoying a puzzle will keep you thinking, it is actually not the best way for someone who already is at a computer all day, to raise their "thought-power".
Thought power isn't necessarily your IQ, but it is the efficiency of essentially, working with what you've got.
The best way to make the most of your computer work? Turn off the computer. All of computer work is essentially verbal or visual coding, in some way. So, to step away from those forms of thought, and into a different focus, like cooking or yoga, while still thinking about your computer work if you wish, will help you to be more efficient.
Get Passionate about your work. While you are away from the computer, start to write out your ideas and get passionate about the potential of your dreams. Then, get feedback or create a discussion from someone who is trusted and supportive of you. This helps you to step outside of your comfort zone which fuels your creativity, which strengthens your thought-power.
Get grouped. When you have a small group of people who you can mastermind with, you'll see that your intelligence is not in your head only but, we are interconnected, and thus, our close group can serve as a cognitive amplifier. Work smarter, not harder.
Pretend you are Shakespeare and get brief. As he has said, "Brevity is the soul of wit". So, try to whittle down your thoughts and focus, so that you can power them up. Imagine water flowing gently through your fingers, and then water coursing through a small funnel. The power of the focused water flow is going to be more powerful. So, get powerful.