i used to be good at making up knock knock jokes. that was till my current dry spell, that's lasted about two years or so.
which is why i'm proud of my last one (which isn't strictly to the form, TBH), but did flow without much effort:
woo hoo, RT @inkv Awesome hues outside!
ps: i have an extremely strong tendency to type knock as "knowck". yes, it always happens. i made that mistake every single time i typed knock in this post. and that's despite being conscious of it, and making a mental note that this quirk should go in the post even!