Someone questioned why use DOD on a Baselisk, when the PCs could just close their eyes and blind fight.
With DOD we can see the room and avoid attacking each other. We can make Spot checks to tell which square the Baselisk is in, or use Glitterdust to reveal the location (that won't reactivate the gaze attack, since it simply outlines the creature.) PCs can avoid other hazards, and can accurately place AoE spells without hurting their friends.
Someone else talked about PCs creating makeshift molotov cocktails from a bottle of oil and rags, and how the D20 rules don't account for AoE attacks with non-magical weapons.
I'd like to welcome this contributor to Basic D&D, where this exact item was detailed in the rules, and where "grenade like missiles" were first introduced. Since then, however, someone came to their senses and realized that olive oil ain't that flameable, and certainly isn't gasoline or even kerosene. That's why the oil-flask as a weapon kind of faded out under D20 and 3.* in favor of Alchemist's Fire. There is, of course, also Alchemical Acid, Liquid Ice, and Holy Water as further samples of relatively common, right-out-of-the-book examples of non-magical AoE attacks, See the Splash Damage rules.
A lot of the discussion has turned to talk of DMs "get you next time" and/or "passive/aggressive" players. That's kind of the reaction that prompted this thread. At what point does a player cross the line from "creative/unexpected use of spell or item" to "looking for trouble"? At what point does the DM cross from "upping his game to face the challenge" to "punishing" PCs who fail to follow the script?
The biggest problem with the game-changer trick is that it often interrupts the game session. The DM literally doesn't know what to do next, they weren't prepared for that abrupt a turn of events.
In a 1st edition tournament game one of the PCs was given a potion of Polymorph Self. Is 1st edition that spell was akin to Shape Shift, in that you could change form multiple times. We were inside a tower, and under time pressure to finish. So the Monk changed into a Rinocerous and my Wizard mounted on his back. We popped the door ahead and charged in. It was a room full of guards that we'd caught by surprise. Our declared action was to simply run acroos the room and through the door on the far side. The DM wanted to know who was opening the door. The answer was "We aren't. We are going through the door. We're on a Rinocerous, we can do that." That ticked the DM off.
Second to last scene was a bttle in a ground floor room, guards protecting a spiral staircase that lead up. My character went Invisible and snuck through and up the stair. The enemy Wizard, a so called Time Lord, was on that stair, preparing to fight the final scene. My character was several rounds ahead of the rest.
The DM got very pissed indeed when my PC one-punched his big bad. The earlier version of Sepia Snake Sigil was one that could be cast as a direct offensive spell, and it froze the victim in time pretty much until the caster wanted to let them out. The snake-like energy would strike at the target as a monster of the caster's level. If it hit, that was it, no Save.
The DM was so upset that he changed the scene in such a way that my character was killed, after we'd won. It was obvious and arbitrary, and the loss of that character was the difference between us winning and losing the tournament.
In an earlier section we had to make our way down a long spiral road around a circular valley with that tower in the center. There were armed guard posts visible along the route, and we were under time pressure. (The DM had taken to intentionally delaying us every time we'd solved something "too fast". We knew we couldn't fight those three battles and make it, so I suggested that we jump off the cliff. We had several magic items that would let PCs land safely. So we jumped, then one PC flew back up with those items so the next team could jump. The DM (and apparently the author) hadn't considered that we might pass a Ring of Feather Fall around this way. The DM nit-picked at eactly when the ring would kick in, or how fast you could descend that way, checking his watch as he did, to make sure to penalize us for bypassing the planned encounters.
We had consistently beaten planned encounters in unorthodox ways, and the DM didn't know how to score us for it, nor how to deal with players who failed to "follow the script". In fact, we ran roughshod over that dungeon.
Note: All characters, gear and spells were pre-gens by the tournament's author. The module was being played at many tables at the same time by different DMs who, in theory, had been briefed and were familiar with the module. There was no munchkinry, no power gaming, no possibility of us ambushing the DM with items or spells he didn't know about.
And we got punished for it.
So I'm careful no to overdo that sort of thing any more.