Wash/scrub medium sized, well shaped potatoes. Remove any sprouting eyes, nasty gashes or grody spots with a paring knife. Poke each potato several times (like 6) with a paring knife or a fork (to let the steam out, I didn't once and one actually exploded all over my oven). You can wrap each potato in a square of tinfoil or rub them with oil and kosher salt, or you can just stick them in the oven naked (the potatoes, not you).
Bake for 1 hour at 400 degrees farenheit. If they're small, 45 min. might be enough. You know they're done when a fork will go through easily.