The wiki on Scientific Misconduct has a non-exhaustive, but a good starting list on some cases, which may be useful for developing presentations. The definitions of different misconduct cases are described.
1992 student paper differentiates misconduct by negligence vs by deliberate actions.
Science on Trial: The Baltimore Case
Collection of articles from the New York Times Archives
Case Summaries Office of Scientific Integrity
This section contains summaries of closed inquiries and investigations