1. Deep Learning. No immediate use for it, but I feel it's an important skill to know.

2. Powershell (on Linux.) I'm already proficient with the traditional shells, but I want to see if this is overall a better CLI and/or scripting environment than, say, Fish. (This was prompted by the recent post about a similar thing newly implemented in Rust.)

3. APL, getting back on it after a long time and potentially writing my own compiler and dialect, if I feel inspired.

4. Consolidating Japanese, mostly the spoken language, because I don't have the time nor will to memorize 1000s of characters. I'm already intermediate level, so at this point I mainly watch movies / shows every day, hoping some of the vocab will stick to my mind.