Prolific maker Stephen Hobley has an interesting idea for protecting your wall-powered projects from self-destructing: add a lightbulb in series with them. The lightbulb acts like a current-limiting resistor, preventing your device from drawing more power than it can handle.

Note that this is not the same thing as using a fuse (which you should also do). The lightbulb hack works by restricting the maximum amount of current a device can draw, while a fuse cuts off the flow of power if it becomes too great.