I enjoy crosswords very much, and for a while I've been loading the free Houston Chronicle crosswords in Xword. Although they indulge in sports references (which I'm useless at) and tend to be a little repetitive, they have nice puns and they have a good variety of difficulties (they follow the US convention of easiest ones on Mondays and hardest ones on Sundays). Incidentally, the repetitiveness seems common to US crosswords — perhaps a side-effect of the US grid style?
However, I like the Guardian's crosswords a lot too. Unlike the Chronicle, they have cryptics, which I like to try my hand at from time to time. The problem is that the Guardian crosswords are only available online via an annoying Java applet or as PDFs. I managed to work around this using the fact that the input to the Java applet is encoded on a screen-scrapable HTML page, and wrote a tool to convert the HTML to the AcrossLite .puz format. To get the reulsting files to work in Xword, I had to write some patches to support British-style grids.
Like debi, but installs packages to a remote host over SSH. Useful when cross-compilating for Debian-based embedded systems.