Mine

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define HOST "semtex.labs.pulltheplug.org"
#define PORT 24000

int main(int argc, char *argv[])  {
  
  int sockfd, i=0;
  char c;
  
  struct hostent *he;
  struct sockaddr_in server;
  
  FILE *fuck;
  
  fuck = fopen("elf", "w");
  
  he = gethostbyname(HOST);
  
  sockfd = socket(AF_INET, SOCK_STREAM, 0);
  
  server.sin_family = AF_INET;
  server.sin_port = htons(PORT);
  server.sin_addr = *((struct in_addr *)he->h_addr);
  memset(&(server.sin_zero), '\0', 8);
  
  connect(sockfd, (struct sockaddr *)&server, sizeof(struct sockaddr));
  
  while(1)  {
    recv(sockfd, &c, 1, 0);
    
    if(c==0)  {
      printf("File Done.\n");
      break;
    }
    
    if(i % 2 == 0)
      fprintf(fuck, "%c", c);
    
    i++;
  }
  
  close(sockfd);
  fclose(fuck);
}

/*

matt@deathstar ~/code/wargames/semtex $ cc level1.c
level1.c:53:2: warning: no newline at end of file
matt@deathstar ~/code/wargames/semtex $ ./a.out
File Done.
matt@deathstar ~/code/wargames/semtex $ ./elf
bash: ./elf: Permission denied
matt@deathstar ~/code/wargames/semtex $ hexdump elf
0000000 457f 464c 0101 0001
0000007
matt@deathstar ~/code/wargames/semtex $ cat elf
ELFmatt@deathstar ~/code/wargames/semtex $

*/