There is also a great device that cooks up to 7 eggs in one go. You add as much water as you need for soft, medium, or hardboiled, and in just a few minutes it is done. Siemens manufactures the one I use.

If this solution won't work for you, you can hard boil more than you need, and then store them (still in their shell) in the fridge for up to a week - possibly longer but I've not tried. Just write an "H" on the shells so you can tell which ones they are!