If you really want to challenge yourself, learn a new skill from someone who doesn't speak your native language and you are a beginner in their native language. I managed to learn how to knit while I lived in France 20 something years ago. The woman I lived with knit and taught me how to get started.
I managed to knit an entire scarf while on trains and waiting for trains while traveling around Europe during college. I never did learn to bind off though. I vaguely remember her showing me, but I think she actually finished it for me. And since its been over 20 years since then, I don't remember how anymore.
I've picked up needles and yarn several times in the intervening years but can't get excited about scarves and didn't feel I had the ability to do anything else. Well, this year one of my goals is to knit socks. Probably doesn't sound like a HUGE goal for you knitters out there, but it is for me. So, since I've got this list of 43 things, I can't wait until the last minute to get going so I'm working the socks. Well, I haven't actually started them but I pulled out my stuff today and a beginner DVD and relearned the basics - cast on, knit and purl. I can't believe how quickly I felt comfortable doing just those things. Now, to find the sock pattern!