Here's one that I think many of us know, but hasn't been brought up in one of these threads to my knowledge: Spellblades.
Spellblades have a 4-sentence description and still manage to include text that can be read as contradicting itself. (I think designer intent is clear but I've been in this argument plenty of times.) To quote:
The issue here, of course, being the word "next," which makes it sound like the spellblade only works once. I don't read it like that, and if you assume that's the case it leads to some weirdness on its own, like an "expired" spellblade still technically being worth 6000 extra GP.Originally Posted by Spellblade
Whereas my assumed reading, where it works every time? That leads to even sillier consequences. So even after you decide which part of the ability description is wrong, you're still making houserules.