What game mechanics etc. do you, the DM, forbid?

[Soel]

I think the rule is exactly the opposite of this. From the Hypertext SRD:

"The square you start out in is not considered threatened by any opponent you can see, and therefore visible enemies do not get attacks of opportunity against you when you move from that square."

- and -

"If, during the process of withdrawing, you move out of a threatened square (other than the one you started in), enemies get attacks of opportunity as normal."

You're right! I've been doing it wrong! Makes so much more sense...

 

[Testament]

No godless Clerics. Ever.

Only humans can ever be Psionically active, and even then, the psionics system is tweaked to be dangerous, and most are Wilders.

Druids, Rangers and Wu Jen all use Telluric Magic, not Divine Magic.

Anyone can find and disable traps, not just Rogues.

Teleportation is DANGEROUS. Dimension Door has a somatic component when you're going somewhere you can't see, and Blink doesn't exist.

Detect Alignment spells will only find someone with a Subtype, or who has a divine connection.

Any book outside the 3 Cores and the Completes is subject to DM approval. Don't even bother coming near me with non-WotC stuff (I don't have squat) or the Race or Environment series without a DAMN GOOD reason. All PrCs are subject to my approval.

All base classes from the PHB and XPH are used, plus Swashbuckler, Hexblade, Warlock, Wu Jen (renamed Spiritspeaker), and Scout.

Wizards are specialists 90% of the time, and Sorcerers all get Eschew Materials for free. Uncosted material components don't have to be whats listed, just something with "a logical connection to the spell's effect".

 

[DungeonmasterCal]

I don't know why I forgot to include this in my first post in this thread; I don't allow deities in my campaigns. I know that goes against the grain of most DM's, but it's just something I've done for a very long time and it works out pretty well. Divine magic is derived from defined sets of beliefs called Paths in my settings.

 

[DanMcS]

Siangham are indeed a real weapon. Siangham came from Malaysia, and are used in a fighting style called Kuntao

(source: http://en.wikipedia.org/wiki/Siangham)

Hey, that's cool. I always wondered where those came from, and just figured they thought monks needed a piercing weapon

 

[davidschwartznz]

Because I don't like the idea of getting out of melee for free.
If you turn your back on something and run away, then an AoO is the least your opponent should get.

The 'withdraw' action does not mean turning tail and running. That would be the 'run' action - which does trigger AoO. Withdrawing means going into a full defence stance and hustling backwards. Having been on both sides of a witdrawal in RL, I can tell you that the D&D rules are fairly realistic in this regard.

 

[painandgreed]

To whomever said they dont allow Spiked chains and Siangham because they arent real;
Siangham are indeed a real weapon. Siangham came from Malaysia, and are used in a fighting style called Kuntao

(source: http://en.wikipedia.org/wiki/Siangham)

That soooo looks like a page some guy put up so he could show the DM and be allowed to use one in the campaign.

 

[Mercule]

That soooo looks like a page some guy put up so he could show the DM and be allowed to use one in the campaign.

A kusari-gama is basically a spiked chain. They definitely exist.