A recent Reddit Thread about some little dragons of C & C++:

http://www.reddit.com/r/programming/comments/wgqwb/contest_craziest_compiler_output_due_to_undefined/

The discussed post:
http://blog.regehr.org/archives/759

Other relative articles:
http://blog.regehr.org/archives/232
http://lwn.net/Articles/278137/

How many of those horrors are left in D?

Bye,
bearophile