One thing which never ceases to fascinate me about the Chinese language is how the meaning of an obsolete or lesser used character may be reworked the into something else.
This character's 囧 actual meaning is "Abutilon Avicennae, a plant of the jute family." But the majority of the population (particularly youth) use it as is an emoticon meaning embarrassed or frustrated. That Chinese characters contain this inherent potential as proprietary internet symbols is remarkable. Perhaps you can work out what this character's alternative pop cultural meaning is : 凸 !
Often slang usage shares similarities with Western usage. The phrase n多的 , where 多的 means "many of" simply comes to mean "a lot of something, a quantity to the power of n". Other memes invoke stories from Chinese history. The number 250 has the alternative meaning of "stupid". The story goes that a historical king put a bounty of 1000 gold pieces on the head of one of his rivals. 4 people came forward, all claiming that they had killed the rival. The incredulous king asked how all 4 of them could possibly have murdered him, and asked what should be done with the bounty. The 4 replied in tandem to split the money, 250 gold pieces each. The king, realizing the latent idiocy of the 4, ordered for them to be removed from his court and executed for deception. In this way the figure 250 has come to be mimetic of stupidity and thoughtlessness...
One other slang expression, admittedly rarely seen on internet forums, but of interest nonetheless is 5213344. The pronunciation "wu er yi san san si si" bears a strong resembleance to "wo ai ni sheng sheng shi shi" meaning "我爱你生生世世” In English: "I love you, you are my everything..." Try writing 5213344 in a text message or card to your partner and see the curious look on their face...