I ran a game this evening - first actual play I've had since November. I just wanted to share a couple of tidbits here while events are still fresh.
Probably the stand-out for me this evening was a random encounter. The players were going through a corridor, and reasoned it would have a secret door; they sent enough characters down it that I actually rolled a 1 on the square with the door and it was revealed. The door went into a pocket, and the players failed their surprise roll. The kobolds on the other side didn't fail theirs, so they took a round of dagger-throwing. The kobolds were evenly numbered but the players, with much better AC, managed to take them down without fatalities. The characters looted the kobold room (I think it was actually the only keyed piece of treasure in the session) and were searching for secret doors when I rolled a 1 on my random monster check.
Now, as a referee I always prepare my listing of random encounters. I wanted something icky, worm-shaped and Cthulhoid, but not too high in hit points, so I rolled up a quick, squishy Spawn of Shub-Niggurath using the charts from Carcosa, and it came out to pretty much exactly the kind of beast I needed: ugly, a bit frightening, totally new and unknown to the players. They thought quickly and used a button on the inside of the secret door room to shut themselves in. Then they got one of those moments of ingenuity that you just can't fabricate: they realized that the door seemed to be able to open or close by pressing a panel, and that they might be able to use this against the Spawn. I rolled a quick check, giving it about a 35% chance that the secret door would work like they expected (not have to recess all the way before it began to close) and it came up in favor of their idea, so they managed to neatly bisect the Spawn. I assigned 2 dice of damage for this; it would've been a save or die if the enemy had been less....thing that should not be-ish. Taking down the remaining half - what, you expected it to just die? - didn't take long, and they discovered that the blood was acidic, which they managed to bottle and sell for a bit of a profit.
Of course, I probably could've come up with a suitably Cthulhoid encounter without the charts in Carcosa, but it was fun to have a whole bunch of different options to stat up the kind of creature I needed for a very particular niche. I was also very pleased with the lateral thinking to get around the fight, which turned the whole thing from a "you see something weird" "we run / kill it" into a memorable encounter.