I quite liked the fireworks display!

Changelog.txt

@@ -9,6 +9,7 @@ Key:
 
 Version 1.4.05-dev
  + Added option to allow refreshing of chunks after block-breaking abilities. (Disabled by default)
+ + Added fireworks effects when a player levels-up, for every 50 levels (configurable)
  = Fixed bug where /addxp was setting instead of adding experience
  = Fixed bug where /addxp was not processessing level-ups for online players
  = Fixed bug which allowed players to share experience with nearby dead players

src/main/java/com/gmail/nossr50/config/Config.java

@@ -115,7 +115,8 @@ public class Config extends AutoUpdateConfigLoader {
     public boolean getDodgeEffectEnabled() { return config.getBoolean("Particles.Dodge", true); }
     public boolean getBleedEffectEnabled() { return config.getBoolean("Particles.Bleed", true); }
     public boolean getGreaterImpactEffectEnabled() { return config.getBoolean("Particles.Greater_Impact", true); }
-    public boolean getLevelUpEffectsEnabled() { return config.getBoolean("Particles.LevelUp", true); }
+    public boolean getLevelUpEffectsEnabled() { return config.getBoolean("Particles.LevelUp_Enabled", true); }
+    public int getLevelUpEffectsTier() { return config.getInt("Particles.LevelUp_Tier", 100); }
 
     /* PARTY SETTINGS */
     public int getAutoPartyKickInterval() { return config.getInt("Party.AutoKick_Interval", 12); }

src/main/java/com/gmail/nossr50/listeners/SelfListener.java

@@ -1,7 +1,6 @@
 package com.gmail.nossr50.listeners;
 
-import java.util.Calendar;
-
+import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
@@ -11,15 +10,27 @@ import com.gmail.nossr50.events.experience.McMMOPlayerLevelUpEvent;
 import com.gmail.nossr50.util.skills.ParticleEffectUtils;
 
 public class SelfListener implements Listener {
+    protected Player player;
+
+    protected float skillValue;
+
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     public void onPlayerLevelUp(McMMOPlayerLevelUpEvent event) {
         if (!Config.getInstance().getLevelUpEffectsEnabled()) {
             return;
         }
 
-        Calendar today = Calendar.getInstance();
-        if (today.get(Calendar.MONTH) == Calendar.APRIL && today.get(Calendar.DAY_OF_MONTH) == 1) {
-            ParticleEffectUtils.runescapeModeCelebration(event.getPlayer(), event.getSkill());
+        int tier = Config.getInstance().getLevelUpEffectsTier();
+
+        if (tier <= 0) {
+            return;
+        }
+
+        player = event.getPlayer();
+        skillValue = event.getSkillLevel();
+
+        if ((skillValue % tier) == 0) {
+            ParticleEffectUtils.runescapeModeCelebration(player, event.getSkill());
         }
     }
 }

src/main/resources/config.yml

@@ -374,4 +374,7 @@ Particles:
     Bleed: true
     Greater_Impact: true
 
-    LevelUp: true
+    # These settings determine if fireworks should get launched when a player levels-up,
+    # this will happen by default for every 50 levels.
+    LevelUp_Enabled: true
+    LevelUp_Tier: 100