An interesting collection of e-mail humor, that points out some inconsistencies in a ruleset. But then, it also makes fun of itself, by laughing at the wrong things. Some of these catches are definite issues, but that's why the book is called the Dungeon Master's Guide. DMs are supposed to make rulings up as they go to maintain consistency. But to address some of the comments that seemed most bogus:

The extreme heat/extreme cold rules render much of the real world uninhabitable as everyone in Fairbanks in winter or Phoenix in summer takes enough subdual damage to render them unconscious in just a few hours.
Yup. I've been in Phoenix in the summer. And, if it weren't for air conditioning and drinking lots of water, odds are, I would've passed out had I tried to adventure around in that weather.
Simulacrum produces a creature that has among other traits 51-60% of the "speech" of the original. Does that mean that it leaves random words out of ... or do it just use small words when talk?
Simulacrum gives you a copy that can't talk as well as the original. It just doesn't use big words.
The 20th level Expert Trapmaker with Search, Profession: Trapmaker, Craft: Trapmaking, Knowledge: Famous Traps and Knowledge: Magical Traps all maxed out at 23 ranks, cannot attempt to find a trap if the Search DC is over 20, but the 1st level rogue with none of those skills can.
Yup. Maybe instead of being such a specialist, he should've spent one level learning how to spot a magical trap. But heck, I know Ph.D.s in the computer sciences that can't figure out how to schedule a meeting in Outlook, which any first level secretary can do.
Running away from someone? Need to block a passage? Well, have we got a solution for you! Summon Monster V allows you to summon a celestial orca. The critter has (on average) 85 hit points and it can thrash around and attack anyone trying to get through. Much better than a wall of stone. (And, since it just goes back to its home plane when it "dies," you don't really have to feel all that bad.)
Of course, you'd be even better off with Stone Shape, since its an instantaneous transmutation, and Dispel Magic won't just blow it away. But then, Douglas Adams has already used the falling giant whale trick.
The various "half-" templates can be applied to any corporeal creature (alignment permitting). This includes oozes, plants and even constructs.
"Can" just implies the possibility. Is there any reason my universe can't have a half-dragon ooze, who gained half-dragoness by absorbing the essence of the avatar of Tiamat after it was killed by the avatar of Bahamut? There's no intercourse requirement.
A house cat, according to the MM, can deal 3 damage with two claws and a bite. (Minimum damage is 1 HP for an attack.) And a peasant has 1d4 HP. So don't tick off kitty!
Yup. The day after I got this in email, I was cutting my parents' Maine coon's claws. He decided he didn't like it, so bit the fleshy part of my hand. Using Improved Grapple, he then executed, as a free action, a rend attack. He then released me and ran. This was a good thing, since I was now at zero hit points and staggered. If I'd tried to do anything strenuous, I'm sure I would have passed out.
A whip cannot even deal subdual damage to any creature with a +3 or better natural armor bonus. This includes all horses, which makes you wonder about coachmen and the use of riding crops.
I'll admit to not being an equestrian, but whips and crops sting. The horse thinks it takes damage, so it adjusts. Kind of like the Disable power, now that I think of it.
Dire Elephants, as described in MotW, have a +23 skill bonus to Climb, and are listed as having speed 40 ft., Climb 10.
Haven't read Masters of the Wild yet, but I'd bet that the Dire Elephant, as a prehistoric type of elephant, has claws, instead of vestigal toenails. Claws for climbing.
Although it ignores armor (as it normally requires only a ranged touch attack to hit), and is specifically noted as creating a "magical arrow", Melf's Acid Arrow cannot be used to perform a Coup de Grace against an adjacent foe in the manner a normal bow can (PHB 133). For that matter, neither can a sling, although a hand crossbow works just fine.
Yup. A coup de grace is a full round action, where you very carefully aim a shot, then fire. Melf's Acid Arrow creates an arrow that is flying at the target, whereas slings, with their spinning, are a bit difficult to make a precise shot.
Despite the really cool part about the ability not allowing a saving throw, that's just clever advertising intended to distract you from the fact that the complete destruction effect of a Mace of Smiting only functions when you deal a critical hit to a construct - which are not subject to the effects of critical hits.
Follow the Rule of Specificity - more specific rules overrule generic rules.
Wizards, druids, and monks do not have Unarmed Strike as a weapon proficiency and the druid loses all abilities for 24 hours if she tries to punch someone, or if she Wild Shapes into an animal and bites them.
Monks do. Why should wizards? How many wizards really train in how to hurt someone with their bare hands? And druids lose their abilities if they wield a prohibited weapon. How do you wield a fang?
A Cleric with the Water Domain can turn Fire Creatures like a normal cleric turns Undead. So Clerics with the Water Domain can turn Red Dragons.
Yup. And, in general, it would take a 12th level cleric, rolling a twenty on their turn check, to turn a young adult dragon. A 12th level party should be able to handle a young adult dragon, don't you think?