diff --git a/src/app.py b/src/app.py
index 4ebb1d9..bd8aa91 100644
--- a/src/app.py
+++ b/src/app.py
@@ -38,6 +38,45 @@
         "schedule": "Mondays, Wednesdays, Fridays, 2:00 PM - 3:00 PM",
         "max_participants": 30,
         "participants": ["john@mergington.edu", "olivia@mergington.edu"]
+    },
+    # Sports related activities
+    "Soccer Team": {
+        "description": "Join the school soccer team and compete in local leagues",
+        "schedule": "Tuesdays and Thursdays, 4:00 PM - 5:30 PM",
+        "max_participants": 18,
+        "participants": ["lucas@mergington.edu", "mia@mergington.edu"]
+    },
+    "Basketball Club": {
+        "description": "Practice basketball skills and play friendly matches",
+        "schedule": "Wednesdays, 3:30 PM - 5:00 PM",
+        "max_participants": 15,
+        "participants": ["liam@mergington.edu", "ava@mergington.edu"]
+    },
+    # Artistic activities
+    "Art Club": {
+        "description": "Explore painting, drawing, and other visual arts",
+        "schedule": "Mondays, 3:30 PM - 5:00 PM",
+        "max_participants": 16,
+        "participants": ["noah@mergington.edu", "isabella@mergington.edu"]
+    },
+    "Drama Society": {
+        "description": "Participate in school plays and drama workshops",
+        "schedule": "Fridays, 4:00 PM - 5:30 PM",
+        "max_participants": 20,
+        "participants": ["amelia@mergington.edu", "jack@mergington.edu"]
+    },
+    # Intellectual activities
+    "Mathletes": {
+        "description": "Compete in math competitions and solve challenging problems",
+        "schedule": "Thursdays, 3:30 PM - 4:30 PM",
+        "max_participants": 10,
+        "participants": ["ethan@mergington.edu", "charlotte@mergington.edu"]
+    },
+    "Science Club": {
+        "description": "Conduct experiments and explore scientific concepts",
+        "schedule": "Wednesdays, 4:00 PM - 5:00 PM",
+        "max_participants": 14,
+        "participants": ["benjamin@mergington.edu", "harper@mergington.edu"]
     }
 }
 
@@ -62,6 +101,10 @@ def signup_for_activity(activity_name: str, email: str):
     # Get the specific activity
     activity = activities[activity_name]
 
+    # Validate student is not already signed up
+    if email in activity["participants"]:
+        raise HTTPException(status_code=400, detail="Already signed up for this activity")
+
     # Add student
     activity["participants"].append(email)
     return {"message": f"Signed up {email} for {activity_name}"}
diff --git a/src/static/app.js b/src/static/app.js
index dcc1e38..d5e1c35 100644
--- a/src/static/app.js
+++ b/src/static/app.js
@@ -12,13 +12,15 @@ document.addEventListener("DOMContentLoaded", () => {
 
       // Clear loading message
       activitiesList.innerHTML = "";
+      activitySelect.innerHTML = ""; // <-- Add this line
 
       // Populate activities list
       Object.entries(activities).forEach(([name, details]) => {
         const activityCard = document.createElement("div");
         activityCard.className = "activity-card";
 
-        const spotsLeft = details.max_participants - details.participants.length;
+        const participants = Array.isArray(details.participants) ? details.participants : [];
+        const spotsLeft = details.max_participants - participants.length;
 
         activityCard.innerHTML = `
           <h4>${name}</h4>
diff --git a/src/static/index.html b/src/static/index.html
index 3074f6e..1a4e16a 100644
--- a/src/static/index.html
+++ b/src/static/index.html
@@ -46,5 +46,46 @@ <h3>Sign Up for an Activity</h3>
     </footer>
 
     <script src="app.js"></script>
+    <script>
+      // Enhance activity card rendering to include participants
+      document.addEventListener("DOMContentLoaded", () => {
+        fetch("/activities")
+          .then(res => res.json())
+          .then(data => {
+            const activitiesList = document.getElementById("activities-list");
+            activitiesList.innerHTML = "";
+            Object.entries(data).forEach(([name, info]) => {
+              const card = document.createElement("div");
+              card.className = "activity-card";
+              card.innerHTML = `
+                <h4>${name}</h4>
+                <p><strong>Description:</strong> ${info.description}</p>
+                <p><strong>Schedule:</strong> ${info.schedule}</p>
+                <p><strong>Max Participants:</strong> ${info.max_participants}</p>
+                <div class="participants-section">
+                  <strong>Participants:</strong>
+                  ${
+                    info.participants.length
+                      ? `<ul class="participants-list">${info.participants.map(
+                          p => `<li>${p}</li>`
+                        ).join("")}</ul>`
+                      : `<span class="no-participants">No participants yet.</span>`
+                  }
+                </div>
+              `;
+              activitiesList.appendChild(card);
+            });
+            // Populate activity dropdown as before
+            const activitySelect = document.getElementById("activity");
+            activitySelect.innerHTML = '<option value="">-- Select an activity --</option>';
+            Object.keys(data).forEach(name => {
+              const opt = document.createElement("option");
+              opt.value = name;
+              opt.textContent = name;
+              activitySelect.appendChild(opt);
+            });
+          });
+      });
+    </script>
   </body>
 </html>
diff --git a/src/static/styles.css b/src/static/styles.css
index a533b32..17ea2f4 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -142,3 +142,30 @@ footer {
   padding: 20px;
   color: #666;
 }
+
+.participants-section {
+  margin-top: 12px;
+  padding: 10px;
+  background: #f1f8e9;
+  border-radius: 4px;
+  border: 1px solid #c5e1a5;
+}
+
+.participants-section strong {
+  color: #388e3c;
+  display: block;
+  margin-bottom: 6px;
+}
+
+.participants-list {
+  margin-left: 18px;
+  margin-bottom: 0;
+  color: #2e7d32;
+  font-size: 15px;
+}
+
+.no-participants {
+  color: #888;
+  font-style: italic;
+  margin-left: 5px;
+}