(>:3) = Space Lions. If you mention them in a sentence, you must cut off the sentence with AHHHGOD MY LIMBS. To repel them, you must use the tank copter. We insert them randomly into IM conversations, or if you want to mention them IRL, it's "Bracket, greater-than sign, semicolon, three, bracket." Also, nug. Nug is an exclamation of anger or annoyance, or just a replacement for actually speaking. Then there is 'FRYPAN REPRESENT!' Which came about during a game of Little Big Planet where I kitted my sackboy out with a big hat and a frypan, and whacked my friend's sackboy with the frypan. I then made my sackboy hold aloft his frypan and said "FRYPAN REPRESENT!" These are jokes that only 1 other person I know actually understands the correct usage of. This friend has also been unofficially dubbed Ringo, because I once described his hair as being like that of 'Ringo Starr, the Beatle nobody likes.' Now if anything is inferior to other, similar things, it is the Ringo Starr of the thing. E.G Rupiah are the Ringo Starr of currency.
A couple of us in my group replace any word meaning annoying, stupid or inexplicable with 'ignorant'. E.g. 'What an ignorant bag of chips' if you cannot open it. For something so ignorant it cannot even be called simply ignorant, we refer to it as 'Bubbish' after the nickname given to a friend's little brother, Bub.
... So many jokes.