E-book readers such as the Kindle
I use mine way more often than I originally expected. The low weight means I can have it in my bag by default. A lot of content is available in e-book format and it’s easy to get onto the device. Reading lengthy articles on it makes me less likely to get distracted by links, email, etc.
The unexpected killer feature for me was that you can use it one-handedly. I’ve been carrying my sleeping daughter and reading at the same time for hours—that would have been impossible or at least prohibitively uncomfortable with a book.
I donated 650$ and will donate the same amount to the CFAR fundraiser.