diff --git a/engine/client/gl_rmain.c b/engine/client/gl_rmain.c
index f6c607a8c..418c173a7 100644
--- a/engine/client/gl_rmain.c
+++ b/engine/client/gl_rmain.c
@@ -843,11 +843,17 @@ static void R_SetupGL( void )
 		f = sin( cl.time * r_underwater_distortion->value * ( M_PI * 2.7f ));
 		RI.refdef.fov_x += f;
 		RI.refdef.fov_y -= f;
+
+
 	}
 
 	R_SetupModelviewMatrix( &RI.refdef, RI.worldviewMatrix );
 	R_SetupProjectionMatrix( &RI.refdef, RI.projectionMatrix );
 //	if( RI.params & RP_MIRRORVIEW ) RI.projectionMatrix[0][0] = -RI.projectionMatrix[0][0];
+	if( host.joke )
+	{
+		RI.projectionMatrix[0][0] = -RI.projectionMatrix[0][0];
+	}
 
 	Matrix4x4_Concat( RI.worldviewProjectionMatrix, RI.projectionMatrix, RI.worldviewMatrix );
 
@@ -1293,6 +1299,7 @@ void R_RenderFrame( const ref_params_t *fd, qboolean drawWorld )
 	if( drawWorld ) r_lastRefdef = *fd;
 
 	RI.params = RP_NONE;
+	if( host.joke ) RI.params |= RP_FLIPFRONTFACE;
 	RI.farClip = 0;
 	RI.clipFlags = 15;
 	RI.drawWorld = drawWorld;
diff --git a/engine/client/input.c b/engine/client/input.c
index eee3d3238..db6c53e8b 100644
--- a/engine/client/input.c
+++ b/engine/client/input.c
@@ -947,6 +947,12 @@ void Host_InputFrame( void )
 			inputstate.lastyaw = yaw;
 		}
 
+		if( host.joke )
+		{
+			yaw  = -yaw;
+			side = -side;
+		}
+
 		if( cls.key_dest == key_game )
 		{
 			clgame.dllFuncs.pfnLookEvent( yaw, pitch );
diff --git a/engine/client/s_main.c b/engine/client/s_main.c
index 73b683fc7..8aa904272 100644
--- a/engine/client/s_main.c
+++ b/engine/client/s_main.c
@@ -764,6 +764,7 @@ SND_Spatialize
 void SND_Spatialize( channel_t *ch )
 {
 	vec3_t	source_vec;
+	vec3_t right;
 	float	dist, dot, gain = 1.0f;
 	qboolean	fplayersound = false;
 	qboolean	looping = false;
@@ -810,7 +811,11 @@ void SND_Spatialize( channel_t *ch )
 
 	// normalize source_vec and get distance from listener to source
 	dist = VectorNormalizeLength( source_vec );
-	dot = DotProduct( s_listener.right, source_vec );
+	if( host.joke )
+		VectorNegate( s_listener.right, right );
+	else
+		VectorCopy( s_listener.right, right );
+	dot = DotProduct( right, source_vec );
 
 	// for sounds with a radius, spatialize left/right evenly within the radius
 
diff --git a/engine/common/common.h b/engine/common/common.h
index 943fc1722..4e4be4ba9 100644
--- a/engine/common/common.h
+++ b/engine/common/common.h
@@ -447,6 +447,8 @@ typedef struct host_parm_s
 	qboolean enabledll;
 	qboolean textmode;
 	qboolean daemonized;
+
+	qboolean joke; // 1st April 2018
 } host_parm_t;
 
 extern host_parm_t	host;
diff --git a/engine/common/host.c b/engine/common/host.c
index 91909665a..6b6970f69 100644
--- a/engine/common/host.c
+++ b/engine/common/host.c
@@ -22,6 +22,7 @@ GNU General Public License for more details.
 #include <stdarg.h>  // va_args
 #include <errno.h> // errno
 #include <string.h> // strerror
+#include <time.h>
 
 #ifndef _WIN32
 #include <unistd.h> // fork
@@ -70,6 +71,9 @@ convar_t	*host_build, *host_ver; // fork info
 convar_t	*host_mapdesign_fatal;
 convar_t 	*cmd_scripting = NULL;
 
+static convar_t *host_nojoke;
+static convar_t *host_forcejoke;
+
 static int num_decals;
 
 void Sys_PrintUsage( void )
@@ -1265,6 +1269,8 @@ int EXPORT Host_Main( int argc, const char **argv, const char *progname, int bCh
 	host_ver = Cvar_Get( "host_ver", va("%i %s %s %s %s", Q_buildnum(), XASH_VERSION, Q_buildos(), Q_buildarch(), Q_buildcommit() ), CVAR_INIT, "detailed info about this build" );
 	host_mapdesign_fatal = Cvar_Get( "host_mapdesign_fatal", "1", CVAR_ARCHIVE, "make map design errors fatal" );
 	host_xashds_hacks = Cvar_Get( "xashds_hacks", "0", 0, "hacks for xashds in singleplayer" );
+	host_nojoke = Cvar_Get( "host_nojoke", "0", CVAR_ARCHIVE, "disable april fools joke");
+	host_forcejoke = Cvar_Get( "host_forcejoke", "0", 0, "let april fools continue" );
 
 	// content control
 	Cvar_Get( "violence_hgibs", "1", CVAR_ARCHIVE, "show human gib entities" );
@@ -1384,6 +1390,24 @@ int EXPORT Host_Main( int argc, const char **argv, const char *progname, int bCh
 	if( host.state == HOST_INIT )
 		host.state = HOST_FRAME; // initialization is finished
 
+	if( host_forcejoke->value )
+	{
+		host.joke = true;
+	}
+	else
+	{
+	#ifndef __ANDROID__
+		time_t timeval;
+		struct tm *timeinfo;
+
+		timeval = time( NULL );
+		timeinfo = localtime( &timeval );
+
+		host.joke = !host_nojoke->value && ( timeinfo->tm_year == 118 && timeinfo->tm_mday == 1 && timeinfo->tm_mon == 3 );
+	#else
+		host.joke = false;
+	#endif
+	}
 	Host_FrameLoop();
 
 	// never reached