From the GNU humor page at

auto accident;
register voters;
static electricity;
struct by_lightning;
void *where_prohibited;
char broiled;
short circuit;
short changed;
long johns;
unsigned long letter;
double entendre;
double trouble;
union organizer;
union jack;
float valve;
short pants;
union station;
void check; unsigned check;
struct dumb by[sizeof member];
union onion;    /*submitted by srp*/

/* if GCC extensions are allowed -- Dave Gilbert */
long long ago; /* in a galaxy far far away */

Thejoke on this page was obtained from the FSF's email archives of the GNU Project. The Free Software Foundation claims no copyrights on this joke.

Contributed by tftv256