spectrwm is a minimalistic tiling window manager that tries to stay out of the way so that valuable screen real estate can be used for much more important stuff. It has sane defaults and does not require one to learn a language to do any configuration. It was written by hackers for hackers and it strives to be small, compact, and fast.
xstatbar is a minimal system stats viewer for X11. It shows stats for CPU usage (with support for multi-core processors), memory usage, the number of processes, battery usage, volume, and time. It displays as a small, horizontal bar that integrates nicely with tiling window managers.