Translation - English-Japanese - welcome to the circus, where we teach monkeys how...

It is just an expression that we use at the Lab sarcastically to make reference to what we are some times asked to do... rather impossible things that we make happend,

Romanized
Sa-kasu ni yo-koso! koko de wa, saru ga tobu yo ni naru kyo-iku o ukete imasu.
Literally
Welcome to the Circus! Here, monkeys receive education which teaches them how to fly.
Notes:
Japanese culture doesn't use sarcasm in the same way as English, so the "joke" isn't very clear: they might think you are actually SUCCEEDING in getting the monkeys to fly...
Also, the same word ("tobu") is used in Japanese for "jump" and "fly." So if you just SAY this in Japanese, they might think: "You're teaching monkeys to jump; Huh? Don't they already know how to do that?"
Fortunately, in the written Japanese, the characters are different: one clearly means "fly," the other, "jump."
However, NOW they're just going to think you used the wrong character, and what you really MEANT to write was "jump" anyway, because as we all know, monkeys can"t "fly"!
So all that to say: Be warned, Japanese people will probably not "get" this "joke"... *_*