I've always preferred longer entries in encounter tables, like hex descriptions. An excellent format is "X, but Y" or a description with a twist, because it focuses on how this encounter is different from your first guess.
A very good example of this is the situation-type encounters of Hidden Kingdom. They outline a situation - like a damsel riding her Palfrey at great speed - and then presents a d6 table of further details if the players interact with her. Only then is it determined if she is enjoying the lands that belong to her, a bandit who has teamed up with a Black Knight, an elf, fleeing from a cruel Powerlord or rushing to aid a lover in distress. I like this a lot because it fills the situation with potential: for a second, the Damsel is all those things. And in fact, you could easily decide that all options are true if you want a richer encounter, instead letting the PCs decide which facet of her personality they want to act on. Punish her for her misdeeds with the Black Knight? Reasonable, but maybe the pursuing Powerlord is a more pressing concern? Or maybe Love is the highest virtue, and all trespasses can be justified if she reaches her lover in time to save his life?
Here are 1d6 towers.
You spot a small tower in the distance. Clinging to a rock it rises over the surrounding foliage like the head of a drowning man, easy to lose sight of forever. Overgrown with vines and in bad repair the tower seems deserted at first, but a sudden shadow or instinct gives you doubt
If the tower is approached, roll 1d6:
1. Only the sturdy walls remain of the tower; into this stone cylinder a spindly troll has climbed, making itself a home. The troll hides from sight and hurls child-sized rocks fallen from the structure to protect its nest. The projectiles deals 3d6 damage on impact and continues skidding and bouncing for another 1d6", dealing half damage to those in its path. Armor has no effect.
The troll has a golden ring in its nest.
2. Built by monks to house them in times of strife, the tower has a plethora of narrow windows and a door that only the tallest ladder can reach. Anticipating their doom the monks burned their sacred texts and drank poison to protect their sacred knowledge, but due to cowardice, fate or divine will one of their lot survived. Ancient and bewildered, he now spends his time recreating the scrolls from faltering memory or contemplating the vial of poison that failed to kill him.
In the library are two scrolls that functions as cleric's spells, but if stained or ever touching the ground, they burst into flame in 1d4 rounds.
3. In the tower lives a band of robbers under the command of Radferd of Suddane. They have few treasures and only a little food, but are well equipped and motivated fighters.
4. A flock of harpies stay in this tower. Dread black against the pale twigs and bones that make up their nests, the harpies come here during spring to collect child-slaves to mine their native mountains. Haughty and prone to opportunistic cruelty, they are formidable fighters but reluctant to fight since any damage can lose them their place in the hierarchy of the flock. If nothing can be gained from combat, they curse or coo at interlopers, drop rocks and feces from above, or circle tirelessly around them to spoil their sleep and alert predators and miscreants to their presence.
2d4-2 children are kept in the tower, hungry and maltreated but eerily well-kempt and clean.
5. Locked inside the tower is a wounded knight. Delirious with fever and weak from loss of blood, he was trapped here by two outlaws who hope to secure a ransom for his life. The outlaws will return in 1d6 days, but the smell of blood will attract local monsters within 1d4 days unless the knight's wounds are treated.
6. A band of goblins led by Gultooth Tuck have made this dank tower their home. The hill and surrounding forest is littered with traps, and while many of them are poorly made their rusty teeth and grime-covered spikes make a powerful deterrent for would-be attackers while also providing the outpost with the occasional animal. The goblins are armed javelins and bows, the arrows of which they demonstratively spit on to further dissuade intruders.
The goblins have been fairly successful in their raids, and among their loot is a enchanted sword.