Imaginarium:
A made-official-by-community archive of open problems in condensed matter physics would be cool. Open for anybody to read or contribute, and sorted by keywords even. I wonder if anybody would be brave enough to post an open problem they actually deemed both cool and tractable, and if it could ever catch on and work for the benefit of the community?
Thoughts and musings about research habits and skills:
The explicit discussion of concrete ways to improve as a researcher is something you encounter surprisingly little of in my experience, at least within physics as far as I'm aware. I like to experiment with different ways to work and develop new skills, and might write down bits and pieces now and then related to this. Probably everything I view as a profound realisation in my own life sounds trivial on the face of it, but if, upon digging further, it was in fact non-trivial to me then perhaps I'm not the only one.
The Farmer and the Fruitpicker - Learning to reflect, and giving structure to the way I approach the meta, in both research and my life, has been one of the biggest contributors to my happiness and excitement since starting my PhD. I wrote down a short overview of my thoughts and experience on the matter. By no means are the ideas and suggestions original or surprising, but I know for one that it's the kind of advice I tend to dismiss for a long time without ever actually implementing it. I advise experimenting with it for a week. If it doesn't catch, who cares you lost maybe an hour or 2 total, but I found the habit stuck very naturally. It's a piece of advice I've come across more in other fields but I believe many scientists practice it.
The Power of a Changing Environment - I wrote this after noticing how important it is for me to consistently change my environment in order to work comfortably and feel most creative. Going beyond the idea of just taking breaks, the importance of a significant shift in environment on multiple timescales. Within the day, within the week, and longer. I imagine this preference might be very personal.
Writing:
I sometimes write the odd short story or screenplay, and find it remarkably restorative.