Public speaking. I joined Toastmasters [1] at the start of the year and highly recommend it. Friendly, supportive atmosphere. Challenging, assuming you're not currently comfortable speaking in front of groups. Lots of people who've been there a while comment on howit's improved their careers. One of the most useful bits is learning to evaluate other people's speeches, a skill which can be applied in a variety of situations, and (so I'm told - I'm still learning) leaves a very positive impression on people.
I am not the world's best public speaker, but I do enjoy it. Some of the things that have made me better at it include realizing:
* I will always be nervous before a performance.
* The audience doesn't know what I'm about to say, so they don't know if I "screw up" most of the time.
* Live demos will go wrong. :)
* Talking to 30 people is actually easier than talking to 3 people, because you don't have to pay individual attention to anyone.
The worst part for me anymore is preparing the slide decks.
Douglas Adams satirised precisely this point with his Zaphod Beeblebrox character in Hitchhiker's Guide to the Galaxy. To quote wikipedia[1], his was "a role that involves no power whatsoever, and merely requires the incumbent to attract attention so no one wonders who's really in charge, a role for which Zaphod was perfectly suited"
I had one of these as a teenager and loved it. Learned Pascal with it, and did a lot of assembly language programming with it (Z80 apparently - I'd forgotten if it was that or 6502). It finally gave up the ghost a few years ago. Makes me quite nostalgic.
"Considering how many fools can calculate, it is surprising that it should be thought either a difficult or a tedious task for any other fool to learn how to master the same tricks.
Some calculus-tricks are quite easy. Some are enormously difficult. The fools who write the textbooks of advanced mathematics (and they are mostly clever fools) seldom take the trouble to show you how easy the easy calculations are. On the contrary, they seem to desire to impress you with their tremendous cleverness by going about it in the most difficult way.
Being myself a remarkably stupid fellow, I have had to unteach myself the difficulties, and now beg to present to my fellow fools the parts that are not hard. Master these thoroughly, and the rest will follow. What one fool can do, another can."
This is unrelated to the topic at hand, but Sam Altmans' blog has, at some point in the past week, been blocked by the corporate firewall I'm behind (large international bank). How long till they block HN, I wonder.
[1] https://www.toastmasters.org/