I used rturk, simple ruby library. It assumes using only ExternalQuestion, so I extend a class to QuestionForm XML format.
HIT on MTurk server
The task was a simple question: when do you working on MTurk? I gave only three options, after work, at work and it is my job, and others options. It was interesting that about half answered "it is my job."
To upload a question, QuesetionForm was used. It supports Formatted Content: XHTML but I didn't use it because I didn't need it. Furthermore, it doesn't support script tag so that it is impossible to validate data before submission.
HIT on external server
The second HIT asked workers to find a funny animal photo for kids. 5 of 24 are url of google search result. 5 of 24 are from the same domain. These results shows that people use shortcuts to minimize time spent.