diff --git a/Cargo.lock b/Cargo.lock
index 3210d13..6f9104b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -183,6 +183,14 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "crossbeam-channel"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.7.2"
@@ -1731,6 +1739,7 @@ dependencies = [
 name = "youmubot-prelude"
 version = "0.1.0"
 dependencies = [
+ "crossbeam-channel 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serenity 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "youmubot-db 0.1.0",
@@ -1763,6 +1772,7 @@ dependencies = [
 "checksum core-foundation 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "25b9e03f145fd4f2bf705e07b900cd41fc636598fe5dc452fd0db1441c3f496d"
 "checksum core-foundation-sys 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e7ca8a5221364ef15ce201e8ed2f609fc312682a8f4e0e3d4aa5879764e0fa3b"
 "checksum crc32fast 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ba125de2af0df55319f41944744ad91c71113bf74a4646efff39afe1f6842db1"
+"checksum crossbeam-channel 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "acec9a3b0b3559f15aee4f90746c4e5e293b701c0f7d3925d24e01645267b68c"
 "checksum crossbeam-deque 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c3aa945d63861bfe624b55d153a39684da1e8c0bc8fba932f7ee3a3c16cea3ca"
 "checksum crossbeam-epoch 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5064ebdbf05ce3cb95e45c8b086f72263f4166b29b97f6baff7ef7fe047b55ac"
 "checksum crossbeam-queue 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c695eeca1e7173472a32221542ae469b3e9aac3a4fc81f7696bcad82029493db"
diff --git a/youmubot-prelude/Cargo.toml b/youmubot-prelude/Cargo.toml
index 5e8e18b..c2eb702 100644
--- a/youmubot-prelude/Cargo.toml
+++ b/youmubot-prelude/Cargo.toml
@@ -9,4 +9,5 @@ edition = "2018"
 [dependencies]
 serenity = "0.8"
 youmubot-db = { path = "../youmubot-db" }
+crossbeam-channel = "0.4"
 reqwest = "0.10"
diff --git a/youmubot-prelude/src/lib.rs b/youmubot-prelude/src/lib.rs
index 1b73b8c..c2c3d6b 100644
--- a/youmubot-prelude/src/lib.rs
+++ b/youmubot-prelude/src/lib.rs
@@ -3,10 +3,12 @@ use std::sync::Arc;
 
 pub mod announcer;
 pub mod args;
+pub mod reaction_watch;
 pub mod setup;
 
 pub use announcer::Announcer;
 pub use args::Duration;
+pub use reaction_watch::{ReactionHandler, ReactionWatcher};
 
 /// The global app data.
 pub type AppData = Arc<RwLock<ShareMap>>;
diff --git a/youmubot-prelude/src/reaction_watch.rs b/youmubot-prelude/src/reaction_watch.rs
new file mode 100644
index 0000000..e522435
--- /dev/null
+++ b/youmubot-prelude/src/reaction_watch.rs
@@ -0,0 +1,72 @@
+use crossbeam_channel::{after, bounded, select, Sender};
+use serenity::{framework::standard::CommandResult, model::channel::Reaction, prelude::*};
+use std::sync::{Arc, Mutex};
+
+/// Handles a reaction.
+///
+/// Every handler needs an expire time too.
+pub trait ReactionHandler {
+    /// Handle a reaction. This is fired on EVERY reaction.
+    /// You do the filtering yourself.
+    fn handle_reaction(&mut self, reaction: &Reaction) -> CommandResult;
+}
+
+impl<T> ReactionHandler for T
+where
+    T: FnMut(&Reaction) -> CommandResult,
+{
+    fn handle_reaction(&mut self, reaction: &Reaction) -> CommandResult {
+        self(reaction)
+    }
+}
+
+/// The store for a set of dynamic reaction handlers.
+#[derive(Debug, Clone)]
+pub struct ReactionWatcher {
+    channels: Arc<Mutex<Vec<Sender<Arc<Reaction>>>>>,
+}
+
+impl TypeMapKey for ReactionWatcher {
+    type Value = ReactionWatcher;
+}
+
+impl ReactionWatcher {
+    /// Create a new ReactionWatcher.
+    pub fn new() -> Self {
+        Self {
+            channels: Arc::new(Mutex::new(vec![])),
+        }
+    }
+    /// Send a reaction.
+    pub fn send(&self, r: Reaction) {
+        let r = Arc::new(r);
+        self.channels
+            .lock()
+            .expect("Poisoned!")
+            .retain(|e| e.send(r.clone()).is_ok());
+    }
+    /// React! to a series of reaction
+    ///
+    /// The reactions stop after `duration`.
+    pub fn handle_reactions(
+        &self,
+        mut h: impl ReactionHandler,
+        duration: std::time::Duration,
+    ) -> CommandResult {
+        let (send, reactions) = bounded(0);
+        {
+            self.channels.lock().expect("Poisoned!").push(send);
+        }
+        let timeout = after(duration);
+        loop {
+            let r = select! {
+                recv(reactions) -> r => h.handle_reaction(&*r.unwrap()),
+                recv(timeout) -> _ => break,
+            };
+            if let Err(v) = r {
+                return Err(v);
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/youmubot-prelude/src/setup.rs b/youmubot-prelude/src/setup.rs
index f503922..ab523cc 100644
--- a/youmubot-prelude/src/setup.rs
+++ b/youmubot-prelude/src/setup.rs
@@ -9,5 +9,9 @@ pub fn setup_prelude(db_path: &Path, data: &mut ShareMap, _: &mut StandardFramew
     crate::announcer::AnnouncerChannels::insert_into(data, db_path.join("announcers.yaml"))
         .expect("Announcers DB set up");
 
+    // Set up the HTTP client.
     data.insert::<crate::HTTPClient>(reqwest::blocking::Client::new());
+
+    // Set up the reaction watcher.
+    data.insert::<crate::ReactionWatcher>(crate::ReactionWatcher::new());
 }