diff --git a/leiningen-core/src/leiningen/core/eval.clj b/leiningen-core/src/leiningen/core/eval.clj
index b8762381..fae3682a 100644
--- a/leiningen-core/src/leiningen/core/eval.clj
+++ b/leiningen-core/src/leiningen/core/eval.clj
@@ -40,6 +40,16 @@
           "NUL"
           "/dev/null")))
 
+(defn prep-tasks
+  "Execute all the prep-tasks. A task can either be a string, or a
+  vector if it takes arguments. see :prep-tasks in sample.project.clj
+  for examples"
+  [{:keys [prep-tasks] :as project}]
+  (doseq [task prep-tasks]
+    (let [[task-name & task-args] (if (vector? task) task [task])
+          task-name (main/lookup-alias task-name project)]
+      (main/apply-task task-name (dissoc project :prep-tasks) task-args))))
+
 ;; # Form Wrangling
 
 (defn prep [project]
@@ -52,9 +62,7 @@
          (main/info "It's possible the specified jar is not in any repository.")
          (main/info "If so, see \"Free-floating Jars\" under http://j.mp/repeatability")
          (main/abort)))
-  (doseq [task (:prep-tasks project)]
-    (main/apply-task (main/lookup-alias task project)
-                     (dissoc project :prep-tasks) []))
+  (prep-tasks project)
   (.mkdirs (io/file (:compile-path project "/tmp")))
   (when-let [prepped (:prepped (meta project))]
     (deliver prepped true)))
diff --git a/sample.project.clj b/sample.project.clj
index 5505c87d..9c097a70 100644
--- a/sample.project.clj
+++ b/sample.project.clj
@@ -73,7 +73,7 @@
   ;; Normally Leiningen runs the javac and compile tasks before
   ;; calling any eval-in-project code, but you can override this with
   ;; the :prep-tasks key to do other things like compile protocol buffers.
-  :prep-tasks ["protoc" "compile"]
+  :prep-tasks [["protobuf" "compile"] "javac" "compile"]
   ;; Warns users of earlier versions of Leiningen.
   :min-lein-version "2.0.0"
   ;; Paths to include on the classpath from each project in the