Check out the deleted questions on Stack Overflow
There are a lot of questions on Stack Overflow, probably a lot than you realise. This is understandable when you consider over 7,000 questions are being asked every day. No I’m not just talking about the 5 million odd that you can access via the questions tab (4,930,418 and counting at time of writing). There are also a ridiculous amount of deleted questions which only users with at least 10,000 reputation can see.
Most of the deleted questions are just plain awful questions that don’t belong on the site. A good number of them however were deleted not because they were particularly poor quality or bad questions, but because they were off-topic and don’t really belong on Stack Overflow, they also may have been too old to migrate to a site like Programmers.
Greg Hewgill created a list of old deleted questions ranked by votes, being outside Stack Overflow so people who don’t have the reputation can check them out. A lot of them are great demonstrations of what not to ask on Stack Overflow now that the rules are much more rigorously defined on what is on-topic. They are a lot of fun though :) check out the list here.