diff --git a/src/context.rs b/src/context.rs
index 954d2f4..e4a310b 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -45,4 +45,8 @@ impl IrcContext {
     pub fn mode(&mut self, channel: &str, modes: &str) {
         self.queue(&format!("MODE {} {}", channel, modes))
     }
+
+    pub fn who(&mut self, channel: &str) {
+        self.queue(&format!("WHO {}", channel))
+    }
 }
diff --git a/src/irc_command.rs b/src/irc_command.rs
index 8c359ad..e126060 100644
--- a/src/irc_command.rs
+++ b/src/irc_command.rs
@@ -6,7 +6,7 @@ macro_rules! make_irc_command_enum {
 
     ($($variant:ident: $value:expr),+) => {
         #[allow(non_camel_case_types)]
-        #[derive(Debug)]
+        #[derive(Debug, PartialEq, Eq, Hash)]
         pub enum IrcCommand {
             UNKNOWN,
             $($variant),+
diff --git a/src/lib.rs b/src/lib.rs
index 7d33159..2a07d38 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -194,6 +194,7 @@ pub struct Irc {
     default_system: Option<StoredSystem>,
     invalid_system: Option<StoredSystem>,
     systems: HashMap<String, StoredSystem>,
+    event_systems: HashMap<IrcCommand, StoredSystem>,
     tasks: Vec<(Duration, StoredSystem)>,
     factory: Arc<RwLock<Factory>>,
 }
@@ -220,6 +221,7 @@ impl Irc {
             default_system: None,
             invalid_system: None,
             systems: HashMap::default(),
+            event_systems: HashMap::default(),
             tasks: Vec::new(),
             factory: Arc::new(RwLock::new(Factory::default())),
         })
@@ -235,6 +237,16 @@ impl Irc {
         self
     }
 
+    pub async fn add_event_system<I, S: for<'a> System + Send + Sync + 'static>(
+        &mut self,
+        evt: IrcCommand,
+        system: impl for<'a> IntoSystem<I, System = S>,
+    ) -> &mut Self {
+        self.event_systems
+            .insert(evt, Box::new(system.into_system()));
+        self
+    }
+
     pub async fn add_default_system<I, S: for<'a> System + Send + Sync + 'static>(
         &mut self,
         system: impl for<'a> IntoSystem<I, System = S>,
@@ -385,6 +397,7 @@ impl Irc {
     }
 
     async fn handle_message<'a>(&mut self, message: &'a IrcMessage<'a>) {
+        self.run_event_system(message).await;
         match message.command {
             IrcCommand::PING => self.event_ping(&message.parameters[0]).await,
             IrcCommand::RPL_WELCOME => self.event_welcome(&message.parameters[1..].join(" ")).await,
@@ -468,6 +481,18 @@ impl Irc {
         )
     }
 
+    pub async fn run_event_system<'a>(&mut self, message: &'a IrcMessage<'a>) {
+        let Some(system) = self.event_systems.get_mut(&message.command) else { return; };
+
+        system.run(
+            &message.prefix.clone().unwrap_or_default(),
+            "",
+            &message.parameters,
+            &mut *self.context.write().await,
+            &mut *self.factory.write().await,
+        );
+    }
+
     pub async fn run_default_system<'a>(
         &mut self,
         prefix: &'a IrcPrefix<'a>,
diff --git a/src/system_params.rs b/src/system_params.rs
index bf82a3e..6f166c3 100644
--- a/src/system_params.rs
+++ b/src/system_params.rs
@@ -137,6 +137,7 @@ impl<'a> SystemParam for Channel<'a> {
     }
 }
 
+#[derive(Debug)]
 pub struct AnyArguments<'a>(&'a [&'a str]);
 
 impl<'a> Deref for AnyArguments<'a> {