diff --git a/benchmark/fib.lua b/benchmark/fib.lua
index 576024a7..841d8379 100644
--- a/benchmark/fib.lua
+++ b/benchmark/fib.lua
@@ -3,4 +3,9 @@ function fib(n)
   return fib(n - 2) + fib(n - 1)
 end
 
-io.write(fib(35) .. "\n")
+local start = os.clock()
+for i = 1, 5 do
+  io.write(fib(30) .. "\n")
+end
+local elapsed = os.clock() - start
+io.write(string.format("elapsed: %.8f\n", elapsed))
diff --git a/benchmark/fib.py b/benchmark/fib.py
index 1ce57cc5..e58ddb06 100644
--- a/benchmark/fib.py
+++ b/benchmark/fib.py
@@ -1,5 +1,10 @@
+import time
+
 def fib(n):
   if n < 2: return n
   return fib(n - 1) + fib(n - 2)
 
-print fib(35)
+start = time.clock()
+for i in range(0, 5):
+  print(fib(30))
+print("elapsed: " + str(time.clock() - start))
\ No newline at end of file
diff --git a/benchmark/fib.rb b/benchmark/fib.rb
new file mode 100644
index 00000000..5f224ea0
--- /dev/null
+++ b/benchmark/fib.rb
@@ -0,0 +1,13 @@
+def fib(n)
+  if n < 2 then
+    n
+  else
+    fib(n - 1) + fib(n - 2)
+  end
+end
+
+start = Time.now
+for i in 0...5
+  puts fib(30)
+end
+puts "elapsed: " + (Time.now - start).to_s
diff --git a/benchmark/fib.wren b/benchmark/fib.wren
index 76973e56..1fef14d9 100644
--- a/benchmark/fib.wren
+++ b/benchmark/fib.wren
@@ -6,4 +6,10 @@ var fib = fn(n) {
   }
 }
 
-io.write(fib.call(35))
+var start = OS.clock
+var i = 0
+while (i < 5) {
+  io.write(fib.call(30))
+  i = i + 1
+}
+io.write("elapsed: " + (OS.clock - start).toString)
diff --git a/benchmark/run_all b/benchmark/run_all
new file mode 100755
index 00000000..6a6164c3
--- /dev/null
+++ b/benchmark/run_all
@@ -0,0 +1,65 @@
+#!/usr/bin/python
+
+import math
+import re
+import subprocess
+import sys
+
+FIB_OUTPUT_PATTERN = re.compile(r"""832040
+832040
+832040
+832040
+832040
+elapsed: (\d+\.\d+)""", re.MULTILINE)
+
+BENCHMARKS = [
+  ("fib", FIB_OUTPUT_PATTERN)
+]
+
+LANGUAGES = [
+  ("wren",   "../build/Release/wren", ".wren"),
+  ("lua",    "lua",                   ".lua"),
+  ("python", "python",                ".py"),
+  ("ruby",   "ruby",                  ".rb")
+]
+
+def calc_stats(nums):
+  """Calculates the mean, median, and std deviation of a list of numbers."""
+  mean = sum(nums) / len(nums)
+  nums.sort()
+  median = nums[(len(nums) - 1) / 2]
+  diffs = ((n - mean) * (n - mean) for n in nums)
+  std_dev = math.sqrt(sum(diffs) / len(nums))
+  return [mean, median, std_dev]
+
+
+def run_benchmark_once(benchmark, language):
+  args = [language[1], benchmark[0] + language[2]]
+  out = subprocess.check_output(args, universal_newlines=True)
+  match = benchmark[1].match(out)
+  if match:
+    return float(match.group(1))
+  else:
+    return None
+
+
+def run_benchmark(benchmark, language):
+  print "{0} - {1:10s}".format(benchmark[0], language[0]),
+
+  times = []
+  for i in range(0, 7):
+    times.append(run_benchmark_once(benchmark, language))
+    sys.stdout.write(".")
+
+  if None in times:
+    print "error"
+    return
+
+  times.sort()
+  stats = calc_stats(times)
+  print " mean: {0:.4f} median: {1:.4f} std_dev: {2:.4f}".format(
+      stats[0], stats[1], stats[2])
+
+for benchmark in BENCHMARKS:
+  for language in LANGUAGES:
+    run_benchmark(benchmark, language)
diff --git a/src/primitives.c b/src/primitives.c
index 03c2e7a0..2ea6204d 100644
--- a/src/primitives.c
+++ b/src/primitives.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 #include "compiler.h"
 #include "primitives.h"
@@ -93,7 +94,7 @@ DEF_PRIMITIVE(num_toString)
 {
   // TODO(bob): What size should this be?
   char temp[100];
-  sprintf(temp, "%g", AS_NUM(args[0]));
+  sprintf(temp, "%.14g", AS_NUM(args[0]));
   return (Value)newString(vm, temp, strlen(temp));
 }
 
@@ -235,6 +236,12 @@ DEF_PRIMITIVE(io_write)
   return args[1];
 }
 
+DEF_PRIMITIVE(os_clock)
+{
+  double time = (double)clock() / CLOCKS_PER_SEC;
+  return NUM_VAL(time);
+}
+
 static const char* CORE_LIB =
 "class Object {}\n"
 "class Bool {}\n"
@@ -244,7 +251,8 @@ static const char* CORE_LIB =
 "class Null {}\n"
 "class String {}\n"
 "class IO {}\n"
-"var io = IO.new\n";
+"var io = IO.new\n"
+"class OS {}\n";
 
 void loadCore(VM* vm)
 {
@@ -301,6 +309,9 @@ void loadCore(VM* vm)
   ObjClass* ioClass = AS_CLASS(findGlobal(vm, "IO"));
   PRIMITIVE(ioClass, "write ", io_write);
 
+  ObjClass* osClass = AS_CLASS(findGlobal(vm, "OS"));
+  PRIMITIVE(osClass->metaclass, "clock", os_clock);
+
   ObjClass* unsupportedClass = newClass(vm, vm->objectClass);
 
   // TODO(bob): Make this a distinct object type.
diff --git a/src/vm.c b/src/vm.c
index 511139b2..fcbffd83 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1031,7 +1031,7 @@ void printValue(Value value)
 #ifdef NAN_TAGGING
   if (IS_NUM(value))
   {
-    printf("%g", AS_NUM(value));
+    printf("%.14g", AS_NUM(value));
   }
   else if (IS_OBJ(value))
   {
@@ -1059,7 +1059,7 @@ void printValue(Value value)
   {
     case VAL_FALSE: printf("false"); break;
     case VAL_NULL: printf("null"); break;
-    case VAL_NUM: printf("%g", AS_NUM(value)); break;
+    case VAL_NUM: printf("%.14g", AS_NUM(value)); break;
     case VAL_TRUE: printf("true"); break;
     case VAL_OBJ:
       switch (value.obj->type)