I think of exploration as finding weird things and poking at them to see what they do.
At the entrance to the cave there is a large rune on the floor, engraved and then painted in. We spent about five minutes debating about it, and tried everything from throwing rocks at it to hitting it really hard with a 10' pole, until I finally decided to just scratch up the paint with a dagger, hopefully preventing it from working if it was a trap or alarm. Everybody else thought I was crazy and stood way back. I scratched at it- and spider-people dropped from the ceiling in front of me. Thus began the combat...
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There is a room, 30' by 30', with a fountain in the middle. Inside the fountain are many coins. As was learned in the last visit to the dungeon, the water will reach up out of the fountain and gruesomely dismember any who disturb it (it seems to have acidic properties). I tried throwing a coin in, standing in one of the entrances ready to run. A watery pseudopod lunged for me, but stopped short, unable to reach beyond the room. We debated various ideas including trying to communicate with it and sacrificing a corpse, until the cleric just decided to throw a flask full of pure alcohol into it. The water went crazy and started flailing around everywhere, though still unable to leave the room. Then he held a torch-flame to the alcohol-infused liquid. There was a massive conflagration, resulting in an unconscious cleric, a now empty fountain full of coins, and an excellent war story.
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One of my adventures was adventured without a single hostile encounter, though we had hired mercenaries and bought mantlets in preparation for a tough fight. We found a dead kobold in a cell, cut him open, and discovered a number of rot grubs in his stomach. I immediately decided to try and collect some in a glass flask (for use as grenade, terror weapon, interrogation tool). I failed a dexterity check, got one in my arm, and had it immediately chopped off at the elbow by an elf with a large axe. My greatsword immediately became useless to me, and that flask of rot grubs was the closest thing to treasure that we found. Thankfully, none of the other party members wanted a share of it very badly.
When you've had adventures like these, you don't doubt the fun of exploration.