Wikipedia says it\'s called a quine and someone gave the code below:
char*s=\"char*s=%c%s%c;main(){printf(s,34,s,34);}\";main(){printf(s,34,s,34);} >
char*s=\"char*s=%c%s%c;main(){printf(s,34,s,34);}\";main(){printf(s,34,s,34);}
main(a){printf(a="main(a){printf(a=%c%s%c,34,a,34);}",34,a,34);}