Easily one of the most elegant and powerful memes I have encountered is that of the meme itself.
The term meme was coined by Richard Dawkins in The Selfish Gene, though the concept was around before that. Memetics is the theory that, like genes, our ideas and cultural concepts replicate and evolve. So, basically, a quantifiable unit of ideas. The metaphor is not entirely accurate, as there are minute chemical processes involved in both that do not necessarily translate, at least not in terms that are widely accepted. But memetics seems to have some philosophic validity, at least for me.
One of the main criticisms against memetics is quite literally that we are still not entirely certain how our brain remembers things. We have no physical evidence of the processes involved when a thought or a memory happens. I, of course, am no expert in neurobiology or anything like that, so all I can come up with is optimistic speculation.
We have found through extensive testing and experimentation, that what we internally experience as "life" is the sum total and collective webbing of neurons that makes up our brain. Each neuron has hundreds of connections to other neurons, allowing for this vast matrix of links. A neuron on it's own is essentially worthless.
What makes the system work is the comparative and cooperative nature of these neurons. There is no "red apple" neuron. However, there are neurons that are fired when your eyes experience the color red. There are also neurons that fire when your olfactory glands detect the scent of an apple, when your taste buds are washed with an apples' sweet juices. So, when you experience an apple, what you are really experiencing is the collected data from your various senses, each neuron being a part of the jigsaw puzzle that becomes the experience, or "memory" of the apple. So, similar to muscle memory, the more exposure to the stimuli, the stronger those connection between neurons become, the stronger the "memory". This learning is universal, and is why the mouse stops eating the electrically charged cheese.
But what if your culture decided that apples were bad, for whatever reason. There would be another set of neurons that would become associated with apples: those that deal with feelings of disgust. Just in the same way someone with strict halal or kosher diets would find pork disgusting. There is no direct physical reason to not "enjoy" an apple, but the feelings of enjoyment or disgust can be linked with the base set of neural associations.
So what I propose is that the "meme" is this very association. It is the set of neurons linked when experiencing an object. Humans all feel the same pain, the same internal chemical responses of pleasure, the same set of reactions. The vast differences in our culture lay in the complex set of these connections.
It may seem unlikely that our brains are really processing this much information at any given time. But, of course, keep in mind that there are around one hundred billion (100,000,000,000) neurons in the average brain, making the web vast and expansive. And because of the expansive nature of our brains, there are nigh infinite possibilities within the framework.
This idea follows into evolutionary psychology. The better your body is at making those new connections between neurons, the more flexible you become, and therefore making it just ever so slightly easier to survive. So while there is no neuron for "fire making", the set of connections: that wood can burn, that sparks are made if two rocks are hit together, are a set of memes that can be passed on. The easier it is for you to learn these things, the more energy can be spent eating, reproducing, et cetera.
So what does this tell us? It mean that culture, while important to our social interactions, is very flexible. Each learned response is a thread in the tapestry of culture. We bond with people who have similar connections because we have the same learned responses of fear, pleasure, pain, or joy as they do, and are essentially using the same set of comparative lenses with which to view the world. It also means that, logically, no one is "right" when it comes to these memes. Someone eating gǒu ròu in China feels no pangs of disgust, nor does a westerner eating hamburger, though if those meals were served elsewhere, you'd have some unhappy costumers.
But that's just they way I've put it together...