There is a story about a Necron tomb world awakening. But instead of the usual menacing emergence, one of the Necron warriors got stuck in the opening of his sarcophagus and just flailed around while his comrades tried to figure out how to free him. It was a rather comical sight in the midst of all that supposed doom and gloom.
The use of miscommunication is great too. Imagine a group of Imperial Guardsmen trying to communicate with an alien race that has a completely different language and cultural understanding. The guardsmen's attempts to be diplomatic while the aliens are completely misinterpreting everything can lead to some truly laugh - out - loud moments. Also, the cultural differences can be exaggerated for comedic effect, such as the aliens thinking the guardsmen's helmets are part of their mating rituals or something equally absurd.
One funny Warhammer 40k story is about an Ork Mekboy who tried to 'improve' a Dreadnought. He ended up adding so many random parts that the Dreadnought looked like a walking junkyard. It was hilarious when it tried to move and parts kept falling off during battle.
One of the hilarious Tumblr stories is about a girl who thought she could tame a squirrel. She started leaving food out for it every day. Eventually, the squirrel got so used to her that it would climb onto her shoulder. But one day, it found a nut in her hair and started pulling at it to get the nut out, causing a big mess.
One of the most hilarious Shaq stories is when he was on a talk show and tried to fit into a small chair. His large frame made it look like he was sitting on a toy chair and he just laughed it off.
There was this inexperienced girl at a dance class. When the instructor told her to do a simple spin, she spun so fast that she lost her balance and landed on a pile of cushions. Everyone in the class burst out laughing, including herself. It was a really comical moment.
A really funny story is about an elephant. It walked right up to a safari jeep, and then it started spraying water from its trunk all over the passengers. They were soaked but couldn't stop laughing.
There's this story where a dog owner let his dog run wild in the neighbor's garden. As repentance, he dressed up his dog as a little gardener, complete with a tiny hoe and watering can, and took a photo of the dog 'working' in the garden and sent it to the neighbor with an apology note. It was really funny and the neighbor forgave him easily.
A rather humorous story involves a man who called 911 because he was locked out of his house in his underwear. He thought it was an emergency situation. The operator tried not to laugh while guiding him to find a way to get help from a neighbor or a locksmith. There was also a call from a lady who thought there was a ghost in her attic. After some investigation, it was just a creaky old house. The operator had to comfort her and explain the situation.
Sure. There was this one story where a Guardsman accidentally fired his lasgun into the air during a parade. Instead of getting in trouble, the officer just laughed it off as a 'new form of salute'.
Sure. There's a story about a Tau Fire Warrior who was trying to communicate with an Imperial Guardsman using hand signals. But they were so misinterpreted that the Guardsman ended up chasing the Tau around thinking he was being taunted. It was really funny to see the confused looks on both of their faces.