No, the 6-second unit of time in 2nd Edition was a segment. The tenth of a minute/round breakdown tied into the d10 used in initiative rolls (which had been a d6 in 1st edition). Something happened on initiative 1, it happened in the first 6 seconds of the round.
segment = 6 seconds
round = 1 minute
turn =10 minutes
-rainy(geek)
By D&D rules, orbital bombardment from any higher than 200 feet is pointless due to terminal velocity, regardless of the object’s shape, provided that it weighs greater than 200 lbs. Assuming a wizard wants to strike the maximum number of targets, he can use a Fly spell to attain a height of around 1400 feet, the minimum at which a one-pound object will deal maximum damage. Attaining this height takes 4.7 minutes and a safe descent takes at least 1.1 minutes, and the spell lasts for one minute per caster level. A sixth level wizard could thus carry 250 one-pound weights inside a Bag of Holding and throw two before descending, having time to throw ten more weights for each additional caster level, to a maximum payload of 141 weights at level twenty. Any person or object struck by one of these takes as much damage as if they were immersed in lava for six seconds, set on fire for two minutes, or stabbed twenty times by a man of above-average strength.
When it comes to Reverse Gravity, a fourteenth level sorcerer can create a pillar of reversed gravity a hundred feet high. A twentieth level sorcerer can feasibly create eighteen such pillars stacked vertically for an 1,800ft or 548m reverse gravity cannon. Assuming the spells are made extended with various metamagic and built from the top down, our reverse gravity cannon will take 1.8 minutes to set up, and will last 2.2 minutes before it starts losing height at a rate of 16 feet per second. Can anyone do the maths on a 548m tall gravity cannon?
Back to our decanter of endless water, it may be possible to measure the effect of the geyser by its side-effects. The back pressure will knock down an average man 45% of the time, where an “average man” can bench press 200lbs and stagger around with it or push a heavy object weighting 500lbs. The damage dealt by the powerful stream of water, with one foot wide stream spouting 5 gallons per second, is enough on average to kill a housecat in five seconds.
Can someone more knowledgeable than myself do the maths on our gravity cannon and housecat-exterminating decanter?
I actually just recently saw a discussion, on another board, of the possibility of a lich hiding his phylactery in orbit. For non-players, a lich is a powerful spellcasting undead creature with a special item called a phylactery: If the lich is destroyed but its phylactery is not, then it just re-forms near its phylactery a few weeks later. An adventurer who slays a lich would probably know this, and hence try to also find and destroy the phylactery. So liches try to safeguard and hide them as much as possible. Since liches (being undead) don’t need to breath, and (being powerful spellcasters) can probably find some way to get to and from orbit, vacuum makes for a pretty good defense.
If I’ve done my calculations correctly, I figure that an object should hit the earth, if dropped from a height of 548 m in a time of about 10.6 seconds. If (and I’m assuming here) the effects of a Reverse Gravity spell cause the object to accelerate upwards with a net acceleration equal to that of gravity (i.e., 9.8 m/s[sup]2[/sup]), then at the end of the acceleration, the projectile will have a velocity of roughly 104 m/s upwards, at a height of 548 m. If we assume the projectile is then to simply fall back to earth (after reaching a peak height of about 1100 m), the velocity upon hitting the ground (neglecting air resistance) should be about 147 m/s. How much damage would that be? I don’t know.
…and of course I could have screwed up my math somewhere. 
It’s entirely possible. In one part of D&D folklore, a character is unexpectedly resurrected after it is discovered that he kept a clone body on the moon. With a magical cloak that allows him to fly, our tireless undead friend can zoom straight up at a rate of 3.4 mph (double if there is no gravity dragging him downward), reaching the mesosphere in nine hours and leaving the outer atmosphere in a month or two. Travelling to the moon this way would take something in the range of four years, although if our undead mage has access to sufficiently powerful magic he can conceivably just teleport.
The question is, could a human skeleton survive an unshielded journey to the moon and back?
This seems off to me—after all, an object in orbit isn’t just floating, stationary, in place. Orbital speed is—what, 15,000 mph, ballpark?
By the way—anyone remember the concept for “space billboards,” putting a 1 square km mylar sheet in orbit, that would have the apparent size and brightness of the moon? Well, in a magical context, could you do something with a setup like this? Like using it to surround a planet with magical sigils for a gigantic spell circle, or something?
Low earth orbit is 17,000mph; the figure lessens with increasing height.
This is assuming you hit. We will ignore maximum range rules since you are throwing down, but you still have to include penalties for range increment. Lets assume he casts Magic Stone, upping his range increment 20’, a much better situation than the pitiful range increment for regular thrown weapons (5’? 10’?). At 1400 feet that means a hit role penalty of -69. So, to have a 50% chance of hitting a totally unarmored average human walking in the open with no cover you need to come up with a +69 attack bonus from somewhere. The best I know of off-hand is True Shot, and that only gives +20 on the next attack.
On the other hand, taking a Bag of Holding full of rocks up to that height and upending it over an offending army or village would produce satisfying results. Since you have effectively zero aim anyway, you may as well go for volume.
Ooooooh… does Ice Storm or an equivalent freezing spell area of effect have to be cast at ground level? You could get to altitude, cast it, then upend the Decanter above it. The water freezes to big chunks of hail as it passes through and bombards the area for the duration of the cold spell.
Sure, unless it gets very unlucky and encounters a micrometeor. Even that would just put a little hole through it.
The speed doesn’t matter. The damage maxes out based on height fallen: “For each 200 pounds of an object’s weight, the object deals 1d6 points of damage, provided it falls at least 10 feet. Distance also comes into play, adding an additional 1d6 points of damage for every 10-foot increment it falls beyond the first (to a maximum of 20d6 points of damage).” (From the SRD)
What, so the ienergy imparted to the object to accelerate it to orbital velocity is cancelled out because it’s “falling”? So if I fired a (big-ass) ballista bolt straight down from the top of a 30 story tower, it would strike the ground with no more energy than if I just dropped it off the tower?
I assume, to use Egon’s immortal phrase from Ghostbusters, “it would be bad.” But how bad would it be, exactly? What would that do to your foe?
Well, assuming you could drop molten Pu (see earlier in the thread about what certain DMs may or may not allow), that’d be at 639.4 C (1182.9 F), with a total weight of about 63 kilos (or about 140 pounds), and depending on the isotopes present, probably well beyond critical mass. So you’re likely to get some kind of boom, though it may not be all that big. You might as well specify weapons-grade Pu-239 to be sure, assuming the DM has allowed you to get this far. Even with no boom, the weight and the heat will finish the enemy off. Probably immediately, but I suppose he could die a pain death from the inherent toxicity of plutonium plus third-degree burns with a concussion thrown in for good measure.
I love this board.
Hey, I don’t write the rules. 
Actually, if you fired a ballista bolt straight down from the top of the tower, by the rules, it would probably do the same damage as if you fired it horizontally at point blank range. (3d6, in the 3.0 SRD, it’s not in the 3.5 one as far as I can tell). Fired from a ballista, the bolt is a missile weapon, not a falling object, and therefore follows a different ruleset.
This is why “rule 0” exists, for good DM’s to interpret the rules that make no sense when taken to extremes.