Yes, Esperanto has been the target of many a joke. For all its praiseworthy qualities, it has a lot that can be mocked. (In the English-speaking world, for example, the verb for “to fare” has a suspicious phonetic resemblence to a wholly unrelated verb…) There’s also an “article” about Esperanto in a certain “dramatic encyclopedia” to which I cannot, in good conscience, link you. (It made me laugh, but we all know I’m on the simple-minded end of the intelligence spectrum!)
While sometimes I feel that jokes at Esperanto’s expense are a series of cheap shots, perpetuated by general ignorance about the language itself and linguistics in general, sometimes the comedy offers a surprisingly effective criticism. It’s not that surprising – satire has been one of the best means of inveighing against problems since the dawn of literacy. For now, I would like to point you toward this forum on XKCD.
XKCD itself is a webcomic, devoted to all sorts of random topics. Apparently, it has examined artificial languages on more than one occasion. While the comic manages to be of a consistently high quality, I’m amazed by the lengthy and well-argued discussion about Esperanto and language linked above. Though I haven’t had the chance to tackle all of it – only the first ten pages or so – what I’ve seen so far is worth a look. Check it out, and be sure to read some comics for a laugh in the meantime.
(La fina cxenero estas sxercajxo. Min surprizis gxia ekzisto.)