diff --git a/lisp/core.carp b/lisp/core.carp
index d9e36f9c..74a4019f 100644
--- a/lisp/core.carp
+++ b/lisp/core.carp
@@ -231,6 +231,7 @@
 (register-builtin "substring" '(:string :int) :string)
 (register-builtin "file_path_component" '(:string) :string)
 (register-builtin "get_input" '() :string)
+(register-builtin "spawn" '((:fn () :void)) :void)
 
 (register-builtin "call" '((:fn () :void)) :void)
 (register-builtin "call1" '((:fn (:int) :void)) :void)
diff --git a/lisp/glfw_test.carp b/lisp/glfw_test.carp
index 2adb98f8..92da3384 100644
--- a/lisp/glfw_test.carp
+++ b/lisp/glfw_test.carp
@@ -43,6 +43,9 @@
       (glVertex3f x y 0.0f)
       (glEnd)))
 
+(defn red ()
+  0.6)
+
 (defn gl-demo ()
   (if (glfwInit)
     (let [window (glfwCreateWindow 640 480 "Yeah!" NULL NULL)]
@@ -52,20 +55,20 @@
             (glfwMakeContextCurrent window)
             (while (not (glfwWindowShouldClose window))
               (do
-                (glClearColor 0.6f 0.85f 0.85f 1.0f)
+                (glClearColor (red) 0.85f 0.85f 1.0f)
                 (glClear gl-color-buffer-bit)
-                (glColor3f 1.0f 0.9f 0.2f)
+                (glColor3f 1.0 0.9f 0.2f)
                 (draw-rect -0.5f -0.5f 1.0f 1.0f)              
                 (glfwSwapBuffers window)
                 (glfwPollEvents)))
             (glfwTerminate))))
     (panic "Failed to initialize glfw.")))
 
-(bake draw-rect)
+;;(bake draw-rect)
 
 ;(def app-ast (lambda-to-ast (code app)))
 ;(def app-asta (annotate-ast app-ast))
 
 ;;(bake-gl-exe)
-(bake* gl-demo '(draw-rect))
+;;(bake* gl-demo '(draw-rect))
 
diff --git a/shared/shared.h b/shared/shared.h
index 78fb8a4f..c342f031 100644
--- a/shared/shared.h
+++ b/shared/shared.h
@@ -136,6 +136,20 @@ void async(void *f) {
   printf("Async done.\n");
 }
 
+void spawn(void (*f)()) {
+  printf("FORK start.\n");
+  int pid = fork();
+  if(pid == 0) {
+    printf("In parent\n");
+    f();
+    printf("FORK done.\n");
+    exit(0);
+  }
+  else {
+    printf("In child\n");
+  }
+}
+
 int last_index_of(string s, char c) {
   int len = strlen(s);
   for(int i = len - 1; i >= 0; i--) {
diff --git a/src/primops.c b/src/primops.c
index 98844498..3328b450 100644
--- a/src/primops.c
+++ b/src/primops.c
@@ -9,6 +9,8 @@
 #include "eval.h"
 #include "reader.h"
 
+#include <unistd.h>
+
 void register_primop(char *name, Primop primop) {
   Obj *o = obj_new_primop(primop);
   env_extend(global_env, obj_new_symbol(name), o);
@@ -1395,3 +1397,18 @@ Obj *p_array_to_list(Obj** args, int arg_count) {
   }
   return list;
 }
+
+Obj *p_spork(Obj** args, int arg_count) {
+  printf("SPORK start.\n");
+  int pid = fork();
+  if(pid == 0) {
+    printf("In parent\n");
+    apply(args[0], NULL, 0);
+    printf("SPORK done.\n");
+    exit(0);
+  }
+  else {
+    printf("In child\n");
+  }
+  return nil;
+}
diff --git a/src/primops.h b/src/primops.h
index 6b241c69..ba8dfed0 100644
--- a/src/primops.h
+++ b/src/primops.h
@@ -63,6 +63,7 @@ Obj *p_builtin_p(Obj** args, int arg_count);
 Obj *p_meta_set_BANG(Obj** args, int arg_count);
 Obj *p_meta_get(Obj** args, int arg_count);
 Obj *p_array_to_list(Obj** args, int arg_count);
+Obj *p_spork(Obj** args, int arg_count);
 
 Obj *register_ffi_internal(char *name, VoidFn funptr, Obj *args, Obj *return_type_obj, bool builtin);
 
diff --git a/src/repl.c b/src/repl.c
index 52bea22c..a57155c0 100644
--- a/src/repl.c
+++ b/src/repl.c
@@ -177,6 +177,7 @@ void env_new_global() {
   register_primop("meta-set!", p_meta_set_BANG);
   register_primop("meta-get", p_meta_get);
   register_primop("array-to-list", p_array_to_list);
+  register_primop("spork", p_spork);
   
   Obj *abs_args = obj_list(type_int);
   register_ffi_internal("abs", (VoidFn)abs, abs_args, type_int, true);