MERP campaign, a few of the players can't make it and the GM decides to give the rest of us a little side quest cuz we showed up. There's a couple of trolls living in a cave stealing from a village. In MERP, trolls are tough, the 3 of us would have been torn apart standing toe to toe with them.

So we did some thinking outside the box, starting with scouting the area around their den. The cave was at the end of a shallow valley in the hills, with a stream running through it. We spent the day gathering rocks at the top of the valley, sharpening stakes and putting them in the stream, and otherwise setting up an ambush. When dusk came the trolls left their lair, and we attacked. The first troll took a rock to the head and fell into the stream and was killed by the stakes. The 2nd troll's leg got crushed by a rock, and was finished off by my bow. The third troll took several rocks, and received a long stun duration. He had reduced movement and actions, so when the mounted guy started firing at him and the troll gave chase, he couldn't catch the horse. Meanwhile, the troll is getting hit by my bow, the horseman's bow, and the hobbit's sling. It eventually goes down, and we kill it.

Three low level players took out 3 trolls without so much as a scratch. The GM just stared at us while we high fived, and he gave us a huge amount of XP and we got all the treasure from the trolls' cave (minus the stuff we returned to the village). Apparently, we weren't supposed to attack the things by ourselves, and were just to keep the trolls from hitting the village again until the other players, and the main fighters, could rejoin us.