Automated testcase reduction is way cool. Lithium is a very nice python tool for that, easy enough to modify (to for example, attempt to not reduce only in chunks that are powers of two in size)
Hand in hand with automated testcase reduction is automated testcase generation. There is a little GNU tool (named spu) hiding away in the GDB sources to do just that.
EA have a custom STL replacement. (EASTL). WxCocoaDialog, and CocoaDialog.
High precision timers for Cell Linux.