diff --git a/Docs/Changelog_sm5.txt b/Docs/Changelog_sm5.txt
index 9c23eb2a21..375d58ed79 100644
--- a/Docs/Changelog_sm5.txt
+++ b/Docs/Changelog_sm5.txt
@@ -8,6 +8,10 @@ ________________________________________________________________________________
 StepMania 5.0 Preview 3 | 2011081?
 --------------------------------------------------------------------------------
 
+2011/08/16
+----------
+* Added PrettyPercent(numerator,denominator) Lua binding. [AJ]
+
 2011/08/14
 ----------
 * [Foreground] Restore Foreground Changes for use in gameplay. Note that it
diff --git a/src/RageUtil.cpp b/src/RageUtil.cpp
index aa43661c66..25073e8d45 100644
--- a/src/RageUtil.cpp
+++ b/src/RageUtil.cpp
@@ -2247,8 +2247,10 @@ static RString MakeUpper( RString s ) { s.MakeUpper(); return s; }
 LuaFunction( Uppercase, MakeUpper( SArg(1) ) )
 LuaFunction( mbstrlen, (int)RStringToWstring(SArg(1)).length() )
 LuaFunction( URLEncode, URLEncode( SArg(1) ) );
+LuaFunction( PrettyPercent, PrettyPercent( FArg(1), FArg(2) ) );
 //LuaFunction( IsHexVal, IsHexVal( SArg(1) ) );
-//LuaFunction( UndocumentedFeature, sm_crash(SArg(1)) );
+static bool UndocumentedFeature( RString s ){ sm_crash(s); return true; }
+LuaFunction( UndocumentedFeature, UndocumentedFeature(SArg(1)) );
 
 /*
  * Copyright (c) 2001-2005 Chris Danford, Glenn Maynard