A computer can be a truly useful kitchen gadget. Don't believe me? Just point your browser to Steep.it and behold! It is a handy chart of tea-steeping times and temperatures, with a timer functionality that works with visual and aural cues, and the flexibility to work it any way you want. You can type various commands right in your browser's address bar: steep.it/2minutes30seconds or steep.it/herbal, for example.
The timer counts down with a color-changing screen effect and dings (and displays a pop-up) when your tea is ready. You can even navigate away from the page, and Steep.it will still continue timing and alert you when it's done. It's cute and free, and you might even find it useful.