The 1st-level Sor/Wiz spell wall of smoke [conj] (Spell Compendium 235) says, in part, that
This spell creates a thin [n.b. for large quantities of thin] wall of black smoke. The wall is stationary once created. The wall blocks sight to a limited degree. Creatures on opposite sides of the wall that cannot see over it gain concealment from each other. A creature can pass through a wall of smoke, but it must make a Fortitude save to avoid being nauseated for 1 round.
At the start of the creature's turn, outside of the wall of smoke, it can see its foe past the wall of smoke (mere concealment being insufficient to block line of sight), and other than the wall of smoke there's a clear path between the creature and its foe. The creature charges its foe, moving 10 ft. therefore 5 ft. into the wall of smoke. The creature fails its Fortitude saving throw upon entering the wall.
What immediate effect does this failed saving throw have on the creature? Does this failed saving throw have any effect on the creature during its next turn?
Note: Yep. The paladin barreled right through the wall of smoke and failed his save. I ruled that his charge was spoiled but that he could, if he wanted, finish a normal move and that he'd recover from the nausea at the start of his next turn, and while that was the right call at the time, I'm not sure if that was the technically correct call.