diff --git a/src/app.py b/src/app.py
index 4ebb1d9..2e2754b 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": "Wednesdays and Fridays, 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": "Tuesdays, 5:00 PM - 6:30 PM",
+        "max_participants": 15,
+        "participants": ["liam@mergington.edu", "ava@mergington.edu"]
+    },
+    # Artistic activities
+    "Art Club": {
+        "description": "Explore painting, drawing, and other visual arts",
+        "schedule": "Thursdays, 3:30 PM - 5:00 PM",
+        "max_participants": 16,
+        "participants": ["grace@mergington.edu", "noah@mergington.edu"]
+    },
+    "Drama Society": {
+        "description": "Participate in acting, stage production, and theater games",
+        "schedule": "Mondays, 4:00 PM - 5:30 PM",
+        "max_participants": 20,
+        "participants": ["ella@mergington.edu", "jack@mergington.edu"]
+    },
+    # Intellectual activities
+    "Math Olympiad": {
+        "description": "Prepare for math competitions and solve challenging problems",
+        "schedule": "Wednesdays, 3:30 PM - 5:00 PM",
+        "max_participants": 10,
+        "participants": ["ethan@mergington.edu", "isabella@mergington.edu"]
+    },
+    "Science Club": {
+        "description": "Conduct experiments and explore scientific concepts",
+        "schedule": "Fridays, 2:00 PM - 3:30 PM",
+        "max_participants": 14,
+        "participants": ["benjamin@mergington.edu", "charlotte@mergington.edu"]
     }
 }
 
@@ -62,6 +101,9 @@ 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="Student already signed up")
     # 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..73acc26 100644
--- a/src/static/app.js
+++ b/src/static/app.js
@@ -20,11 +20,32 @@ document.addEventListener("DOMContentLoaded", () => {
 
         const spotsLeft = details.max_participants - details.participants.length;
 
+        // Build participants list HTML
+        let participantsHTML = "";
+        if (details.participants.length > 0) {
+          participantsHTML = `
+            <ul class="participants-list">
+              ${details.participants
+                .map(
+                  (p) =>
+                    `<li><span class="participant-icon">👤</span> ${p.name || p.email || p}</li>`
+                )
+                .join("")}
+            </ul>
+          `;
+        } else {
+          participantsHTML = `<div class="no-participants">No participants yet.</div>`;
+        }
+
         activityCard.innerHTML = `
           <h4>${name}</h4>
           <p>${details.description}</p>
           <p><strong>Schedule:</strong> ${details.schedule}</p>
           <p><strong>Availability:</strong> ${spotsLeft} spots left</p>
+          <div class="participants-section">
+            <div class="participants-title">Participants</div>
+            ${participantsHTML}
+          </div>
         `;
 
         activitiesList.appendChild(activityCard);
diff --git a/src/static/styles.css b/src/static/styles.css
index a533b32..3d8e7b5 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -63,6 +63,7 @@ section h3 {
   border: 1px solid #ddd;
   border-radius: 5px;
   background-color: #f9f9f9;
+  position: relative;
 }
 
 .activity-card h4 {
@@ -142,3 +143,45 @@ footer {
   padding: 20px;
   color: #666;
 }
+
+.participants-section {
+  margin-top: 18px;
+  padding: 12px 14px;
+  background: #eef3fa;
+  border-radius: 7px;
+  border: 1px solid #dde6f3;
+}
+
+.participants-title {
+  font-weight: 600;
+  color: #1a237e;
+  margin-bottom: 8px;
+  font-size: 1.05em;
+  letter-spacing: 0.5px;
+}
+
+.participants-list {
+  list-style: none;
+  padding-left: 0;
+  margin: 0;
+}
+
+.participants-list li {
+  margin-bottom: 6px;
+  padding-left: 0;
+  color: #333;
+  display: flex;
+  align-items: center;
+  font-size: 0.98em;
+}
+
+.participant-icon {
+  margin-right: 7px;
+  font-size: 1.1em;
+}
+
+.no-participants {
+  color: #888;
+  font-style: italic;
+  font-size: 0.97em;
+}