The Warp Speed Calculator
widget isn't useful at all, unless you happen to be a captain of a Starfleet
vessel, but I'm OK with that. As you might expect this simple widget calculates how fast, in km/s, a particular Warp Factor is (from Star Trek: The Next Generation). I can also calculate how long it'll take you to travel distances based on your Warp Factor.
Who doesn't need to know this stuff from time to time?