i've been fucking with greek espresso lately. its stone ground, and you add a tablespoon per cup of boiling water in a regular steel pot. grounds settle at the bottom after you drink it. i make it real strong in the morning and about 15 minutes later i run to the bathroom and blast out a monster shit. if i don't drink it i don't shit and i get a headache. right now i'm drinking about 4-6 strong 8 ounce cups a day.
gunpowder tea is good for caffeine kicks too.