diff --git a/src/app.py b/src/app.py
index fd0c462..a97e835 100644
--- a/src/app.py
+++ b/src/app.py
@@ -38,6 +38,42 @@
         "schedule": "Mondays, Wednesdays, Fridays, 2:00 PM - 3:00 PM",
         "max_participants": 30,
         "participants": ["john@mergington.edu", "olivia@mergington.edu"]
+    },
+    "Soccer Team": {
+        "description": "Join the school soccer team and compete in matches",
+        "schedule": "Tuesdays and Thursdays, 4:00 PM - 5:30 PM",
+        "max_participants": 22,
+        "participants": ["liam@mergington.edu", "noah@mergington.edu"]
+    },
+    "Basketball Team": {
+        "description": "Practice and compete in basketball tournaments",
+        "schedule": "Wednesdays and Fridays, 3:30 PM - 5:00 PM",
+        "max_participants": 15,
+        "participants": ["ava@mergington.edu", "mia@mergington.edu"]
+    },
+    "Art Club": {
+        "description": "Explore various art techniques and create your own masterpieces",
+        "schedule": "Thursdays, 3:30 PM - 5:00 PM",
+        "max_participants": 15,
+        "participants": ["amelia@mergington.edu", "isabella@mergington.edu"]
+    },
+    "Drama Club": {
+        "description": "Participate in plays and improve your acting skills",
+        "schedule": "Mondays and Wednesdays, 4:00 PM - 5:30 PM",
+        "max_participants": 20,
+        "participants": ["elijah@mergington.edu", "lucas@mergington.edu"]
+    },
+    "Math Club": {
+        "description": "Solve challenging math problems and prepare for competitions",
+        "schedule": "Tuesdays, 3:30 PM - 4:30 PM",
+        "max_participants": 10,
+        "participants": ["charlotte@mergington.edu", "harper@mergington.edu"]
+    },
+    "Science Club": {
+        "description": "Conduct experiments and explore scientific concepts",
+        "schedule": "Fridays, 3:30 PM - 5:00 PM",
+        "max_participants": 12,
+        "participants": ["henry@mergington.edu", "jack@mergington.edu"]
     }
 }
 
@@ -62,6 +98,14 @@ def signup_for_activity(activity_name: str, email: str):
     # Get the specificy activity
     activity = activities[activity_name]
 
+    # validate if the student is already signed up
+    if email in activity["participants"]:
+        raise HTTPException(status_code=400, detail="Already signed up for this activity")
+    
+    # validate if the activity is full
+    if len(activity["participants"]) >= activity["max_participants"]:
+        raise HTTPException(status_code=400, detail="Activity is full")
+
     # 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..0a8e58f 100644
--- a/src/static/app.js
+++ b/src/static/app.js
@@ -25,6 +25,14 @@ document.addEventListener("DOMContentLoaded", () => {
           <p>${details.description}</p>
           <p><strong>Schedule:</strong> ${details.schedule}</p>
           <p><strong>Availability:</strong> ${spotsLeft} spots left</p>
+          <div class="participants">
+            <strong>Participants:</strong>
+            <ul>
+              ${details.participants.length > 0 
+                ? details.participants.map(participant => `<li>${participant}</li>`).join("") 
+                : "<li>No participants yet</li>"}
+            </ul>
+          </div>
         `;
 
         activitiesList.appendChild(activityCard);
diff --git a/src/static/styles.css b/src/static/styles.css
index a533b32..3d24c78 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -142,3 +142,22 @@ footer {
   padding: 20px;
   color: #666;
 }
+
+.participants {
+  margin-top: 15px;
+  padding: 10px;
+  background-color: #f1f8e9;
+  border: 1px solid #c5e1a5;
+  border-radius: 5px;
+}
+
+.participants ul {
+  margin: 0;
+  padding-left: 20px;
+  list-style-type: disc;
+}
+
+.participants li {
+  margin-bottom: 5px;
+  color: #2e7d32;
+}