A long time ago, John Regehr wrote a very nice quiz about C integers. He's a pretty awesome expert on undefined behavior and this quiz highlights the type of stuff you need to know when auditing C code. A lot of times you’ll run into really strange scenarios which end up causing exploitable bugs later in the code.
The original version was taken down long ago for reasons of WordPress compatability. I've taken an archival version and wrapped it in simple JavaScript that should work on all browsers.
A few clarification that came up from Twitter threads and reddit.
If you enjoyed this quiz, please follow John Regehr on Twitter. You're also invited to follow me Ace Pace.