diff --git a/src/me/cwang/discosheep/DiscoCommands.java b/src/me/cwang/discosheep/DiscoCommands.java
index 2517c20..6129e4c 100644
--- a/src/me/cwang/discosheep/DiscoCommands.java
+++ b/src/me/cwang/discosheep/DiscoCommands.java
@@ -57,11 +57,15 @@ public class DiscoCommands implements CommandExecutor {
             }
         }
 
+        if (args.length == 0) {
+            return plugin.helpCommand(sender);
+        }
+
         PartyBuilder builder = new PartyBuilder(player);
         // ctor takes "program name" as first arg so we pass the sub-command as that
         // args then start at args[1] so we slice args[1:]
         Getopt g = new Getopt(args[0], Arrays.copyOfRange(args, 1, args.length), "n:t:p:r:g:lfjPb:");
-
+        g.setOpterr(false); // do own error handling
         int c;
         while ((c = g.getopt()) != -1) {
             try {
@@ -95,8 +99,8 @@ public class DiscoCommands implements CommandExecutor {
                                 try {
                                     String[] pair = tokens.nextToken().split(":");
                                     builder.guests(pair[0], Integer.parseInt(pair[1]));
-                                } catch (Exception e) {
-                                    throw new IllegalArgumentException("Bad guest arguments");
+                                } catch (ArrayIndexOutOfBoundsException e) {
+                                    throw new IllegalArgumentException("a valid list of guest:number pairs was not found.");
                                 }
                             }
                         }
@@ -117,9 +121,18 @@ public class DiscoCommands implements CommandExecutor {
                     case 'b':
                         builder.baby(Integer.parseInt(g.getOptarg()));
                         break;
+                    case '?': // handle invalid switch
+                        // need to cast getOptopt() to char because it returns a string representation of an integer
+                        sender.sendMessage(String.format("Invalid switch '%s' was found", (char)g.getOptopt()));
+                        return false;
                 }
-            } catch (IllegalArgumentException e) {
+            } catch (NumberFormatException e) {
+                String badNumber = e.getMessage().replace("For input string: ", "");
+                sender.sendMessage(String.format("Error: %s is not a valid number", badNumber));
+                return false;
+            } catch (IllegalArgumentException e) { // handle invalid arguments
                 sender.sendMessage("Bad command: " + e.getMessage());
+                return false;
             }
         }
 
diff --git a/src/me/cwang/discosheep/DiscoSheep.java b/src/me/cwang/discosheep/DiscoSheep.java
index abafb0d..5e4bd81 100644
--- a/src/me/cwang/discosheep/DiscoSheep.java
+++ b/src/me/cwang/discosheep/DiscoSheep.java
@@ -175,13 +175,9 @@ public final class DiscoSheep extends JavaPlugin {
         }
 	}
 
-	public boolean hasParty(String name) {
-		return parties.containsKey(name);
-	}
+	public boolean hasParty(String name) { return parties.containsKey(name); }
 
-	public AbstractParty getParty(String name) {
-		return parties.get(name);
-	}
+	public AbstractParty getParty(String name) { return parties.get(name); }
 
 	public void removeParty(String name) {
 		if (this.hasParty(name)) {
@@ -234,7 +230,7 @@ public final class DiscoSheep extends JavaPlugin {
                 if (!hasParty(s.getName())) {
                     builder.build().startDisco();
                 } else {
-                    s.sendMessage(ChatColor.RED + "You already have a party. Are you underground?");
+                    s.sendMessage(ChatColor.RED + "You already have a party.");
                 }
                 return true;
             }
diff --git a/src/me/cwang/discosheep/PartyBuilder.java b/src/me/cwang/discosheep/PartyBuilder.java
index 5613237..e48fb74 100644
--- a/src/me/cwang/discosheep/PartyBuilder.java
+++ b/src/me/cwang/discosheep/PartyBuilder.java
@@ -30,7 +30,7 @@ public class PartyBuilder {
 
     public PartyBuilder duration(int duration) throws IllegalArgumentException {
         if (duration < 0 || duration > AbstractParty.maxDuration) {
-            throw new IllegalArgumentException("Invalid duration.");
+            throw new IllegalArgumentException("nvalid duration");
         }
         this.duration = duration;
         return this;
@@ -38,7 +38,7 @@ public class PartyBuilder {
 
     public PartyBuilder radius(int radius) throws IllegalArgumentException {
         if (radius < 0 || radius > AbstractParty.maxRadius) {
-            throw new IllegalArgumentException("Invalid radius.");
+            throw new IllegalArgumentException("Invalid radius");
         }
         this.radius = radius;
         return this;
@@ -51,7 +51,7 @@ public class PartyBuilder {
 
     public PartyBuilder period(int period) throws IllegalArgumentException {
         if (period < 0 || period > AbstractParty.maxPeriod) {
-            throw new IllegalArgumentException("Invalid period.");
+            throw new IllegalArgumentException("invalid period");
         }
         this.period = period;
         return this;
@@ -59,7 +59,7 @@ public class PartyBuilder {
 
     public PartyBuilder sheep(int sheep) throws IllegalArgumentException {
         if (sheep < 0 || sheep > AbstractParty.maxSheep) {
-            throw new IllegalArgumentException("Invalid sheep number");
+            throw new IllegalArgumentException("invalid sheep number");
         }
         this.sheep = sheep;
         return this;
@@ -71,7 +71,7 @@ public class PartyBuilder {
         try {
             type = EntityType.valueOf(key);
         } catch (IllegalArgumentException e) {
-            throw new IllegalArgumentException(String.format("Invalid guest: %s", key));
+            throw new IllegalArgumentException(String.format("invalid guest %s", key));
         }
         if (guests.containsKey(type)) {
             if (n <= AbstractParty.getMaxGuestNumbers().get(type) && n >= 0) { // so that /ds defaults can take 0 as arg
@@ -79,7 +79,7 @@ public class PartyBuilder {
                 return this;
             }
         }
-        throw new IllegalArgumentException(String.format("Invalid number for %s", key));
+        throw new IllegalArgumentException(String.format("invalid number for %s", key));
     }
 
     public PartyBuilder noGuests() {