Flowgrind is a tool similar to iperf or netperf. It measures throughput and other metrics for TCP and other protocols. It features some unique characteristics: a distributed architecture, sophisticated flow scheduling, Linux kernel TCP statistics, the Anderson-Darling statistical test, rate-limited flows with uniform or Poisson distribution, and separation between control and test traffic.
DR14 T.meter is a commandline tool for computing the Dynamic Range of your music according to the procedure used in the offline meter released by the Pleasurize Music Foundation. It is very useful to measure how loud your music is and to understand that a good quality album always has a good dynamic. It's also useful for understanding the effects of the so-called loudness war.
JS Measurer measures a webpage's width and height interactively. It lets the user define an area in the page by dragging the mouse pointer. The object renders the area outline as the mouse moves, showing the width and height of the area in pixels, as well the coordinates of the top-left corner of the area. A bookmarklet is also available, so this object can be used as a link placed, for instance, in the browser toolbar.