[language-agnostic] What is the coolest thing you can do in <10 lines of simple code? Help me inspire beginners!

This is cheating, and not even remotely simple, but I once wrote a shoot'em up in 20 lines of C++, using the Allegro graphics library. No real criteria for what a line was, but it was a bit ago, and it was made purely for fun. It even had crude sound effects.

Here's what it looked like:

20 Lines http://img227.imageshack.us/img227/8770/20linesxx0.png

And here's the code (should compile):

bool inside(int x, int y, int x2, int y2) { return (x>x2&&x<x2+20&&y>y2&&y<y2+10); }
int main() {
  BITMAP* buffer;
  float px,shotx,shoty,monstars[8],first,rnd,pressed,points = 0, maxp = 0;
  unsigned char midi[5] = {0xC0,127,0x90,25,0x54}, plgfx[] = {0,0,0,10,3,10,3,5,6,5,6,10,8,12,10,10,10,5,13,5,13,10,16,10,16,0,13,0,13,2,3,2,3,0,0,0}, mongfx[] = {0,0, 10,5, 20,0, 17,8, 15,6, 10,16, 5,6, 3,8, 0,0};
  allegro_init(), set_color_depth(32), set_gfx_mode(GFX_AUTODETECT_WINDOWED,320,240,0,0), install_timer(), install_keyboard(),  install_mouse(), buffer = create_bitmap(320,240),srand(time(NULL)),install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT,""),clear_to_color(buffer,makecol32(100,100,255));
    while ((pressed=(!key[KEY_Z]&&pressed)?0:pressed)?1:1&&(((shoty=key[KEY_Z]&&shoty<0&&pressed==0?(pressed=1?200:200):first==0?-1:shoty)==200?shotx=px+9:0)==9999?1:1) && 1+(px += key[KEY_LEFT]?-0.1:0 + key[KEY_RIGHT]?0.1:0) && 1+int(px=(px<0?0:(px>228?228:px))) && !key[KEY_ESC]) {
    rectfill(buffer,0,0,244,240,makecol32(0,0,0));
    for(int i=0;i<8;i++) if (inside(shotx,shoty,i*32,monstars[i])) midi_out(midi,5);
        for (int i=0; i<8; monstars[i] += first++>8?(monstars[i]==-100?0:0.02):-100, points = monstars[i]>240?points-1:points, monstars[i]=monstars[i]>240?-100:monstars[i], points = inside(shotx,shoty,i*32,monstars[i])?points+1:points, (monstars[i] = inside(shotx,shoty,i*32,monstars[i])?shoty=-1?-100:-100:monstars[i]), maxp = maxp>points?maxp:points, i++) for (int j=1; j<9; j++) line(buffer,i*32+mongfx[j*2 - 2],monstars[i]+mongfx[j*2-1],i*32+mongfx[j*2],monstars[i]+mongfx[j*2+1],makecol32(255,0,0));
    if (int(first)%2000 == 0 && int(rnd=float(rand()%8))) monstars[int(rnd)] = monstars[int(rnd)]==-100?-20:monstars[int(rnd)]; // randomowe pojawianie potworkow
    if (shoty>0) rectfill(buffer,shotx,shoty-=0.1,shotx+2,shoty+2,makecol32(0,255,255)); // rysowanie strzalu
    for (int i=1; i<18; i++) line(buffer,px+plgfx[i*2 - 2],200-plgfx[i*2-1],px+plgfx[i*2],200-plgfx[i*2+1],makecol32(255,255,0));
    textprintf_ex(buffer,font,250,10,makecol32(255,255,255),makecol32(100,100,255),"$: %i   ",int(points)*10);
    textprintf_ex(buffer,font,250,20,makecol32(255,255,255),makecol32(100,100,255),"$$ %i   ",int(maxp)*10);
    blit(buffer, screen, 0, 0, 0, 0, 320,240);
  }
} END_OF_MAIN()