diff --git a/src/app.py b/src/app.py
index 4ebb1d9..0310435 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": "Thursdays, 4:00 PM - 5:30 PM",
+        "max_participants": 20,
+        "participants": ["amelia@mergington.edu", "benjamin@mergington.edu"]
+    },
+    # Intellectual activities
+    "Math Olympiad": {
+        "description": "Prepare for math competitions and solve challenging problems",
+        "schedule": "Fridays, 2:00 PM - 3:30 PM",
+        "max_participants": 10,
+        "participants": ["charlotte@mergington.edu", "elijah@mergington.edu"]
+    },
+    "Science Club": {
+        "description": "Conduct experiments and explore scientific concepts",
+        "schedule": "Wednesdays, 4:00 PM - 5:00 PM",
+        "max_participants": 14,
+        "participants": ["harper@mergington.edu", "james@mergington.edu"]
     }
 }
 
@@ -62,6 +101,11 @@ def signup_for_activity(activity_name: str, email: str):
     # Get the specific activity
     activity = activities[activity_name]
 
+    # Check if student is already signed up
+    if email in activity["participants"]:
+        raise HTTPException(status_code=400, detail="Student is 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..d23ab96 100644
--- a/src/static/app.js
+++ b/src/static/app.js
@@ -20,11 +20,19 @@ document.addEventListener("DOMContentLoaded", () => {
 
         const spotsLeft = details.max_participants - details.participants.length;
 
+        const participantsList = details.participants.length > 0 
+          ? `<ul class="participants-list">${details.participants.map(email => `<li>${email}</li>`).join('')}</ul>`
+          : '<p class="no-participants">No participants yet</p>';
+
         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">
+            <p><strong>Participants:</strong></p>
+            ${participantsList}
+          </div>
         `;
 
         activitiesList.appendChild(activityCard);
diff --git a/src/static/styles.css b/src/static/styles.css
index a533b32..c8ee032 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -74,6 +74,30 @@ section h3 {
   margin-bottom: 8px;
 }
 
+.participants-section {
+  margin-top: 15px;
+  padding-top: 10px;
+  border-top: 1px solid #e0e0e0;
+}
+
+.participants-list {
+  margin: 8px 0 0 20px;
+  padding: 0;
+}
+
+.participants-list li {
+  margin-bottom: 4px;
+  color: #666;
+  font-size: 14px;
+}
+
+.no-participants {
+  margin: 8px 0 0 0 !important;
+  color: #999;
+  font-style: italic;
+  font-size: 14px;
+}
+
 .form-group {
   margin-bottom: 15px;
 }