diff --git a/src/app.py b/src/app.py
index 4ebb1d9..3553f4c 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 activities
+    "Soccer Team": {
+        "description": "Join the school soccer team and compete in matches",
+        "schedule": "Wednesdays, 4:00 PM - 5:30 PM",
+        "max_participants": 22,
+        "participants": ["alex@mergington.edu", "lucas@mergington.edu"]
+    },
+    "Basketball Club": {
+        "description": "Practice basketball skills and play friendly games",
+        "schedule": "Mondays, 3:30 PM - 5:00 PM",
+        "max_participants": 15,
+        "participants": ["mia@mergington.edu", "noah@mergington.edu"]
+    },
+    # Artistic activities
+    "Art Workshop": {
+        "description": "Explore painting, drawing, and sculpture techniques",
+        "schedule": "Thursdays, 4:00 PM - 5:30 PM",
+        "max_participants": 18,
+        "participants": ["ava@mergington.edu", "liam@mergington.edu"]
+    },
+    "Drama Club": {
+        "description": "Act, direct, and produce school plays and performances",
+        "schedule": "Tuesdays, 3:30 PM - 5:00 PM",
+        "max_participants": 20,
+        "participants": ["ella@mergington.edu", "jack@mergington.edu"]
+    },
+    # Intellectual activities
+    "Debate Team": {
+        "description": "Develop public speaking and argumentation skills",
+        "schedule": "Fridays, 4:00 PM - 5:30 PM",
+        "max_participants": 16,
+        "participants": ["chloe@mergington.edu", "ethan@mergington.edu"]
+    },
+    "Math Club": {
+        "description": "Solve challenging math problems and prepare for competitions",
+        "schedule": "Wednesdays, 3:30 PM - 4:30 PM",
+        "max_participants": 14,
+        "participants": ["zoe@mergington.edu", "ben@mergington.edu"]
     }
 }
 
@@ -62,6 +101,10 @@ def signup_for_activity(activity_name: str, email: str):
     # Get the specific activity
     activity = activities[activity_name]
 
+    # Validate email is not already signed up
+    if email in activity["participants"]:
+        raise HTTPException(status_code=400, detail="Email 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..f1aa73c 100644
--- a/src/static/app.js
+++ b/src/static/app.js
@@ -20,13 +20,35 @@ document.addEventListener("DOMContentLoaded", () => {
 
         const spotsLeft = details.max_participants - details.participants.length;
 
+        // Create participants section safely
+        let participantsSection = document.createElement("div");
+        participantsSection.className = "participants-section";
+        const participantsHeader = document.createElement("h5");
+        participantsHeader.textContent = "Participants:";
+        participantsSection.appendChild(participantsHeader);
+        if (details.participants.length > 0) {
+          const ul = document.createElement("ul");
+          ul.className = "participants-list";
+          details.participants.forEach(email => {
+            const li = document.createElement("li");
+            li.textContent = email;
+            ul.appendChild(li);
+          });
+          participantsSection.appendChild(ul);
+        } else {
+          const p = document.createElement("p");
+          p.className = "no-participants";
+          p.textContent = "No participants yet";
+          participantsSection.appendChild(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>
         `;
-
+        activityCard.appendChild(participantsSection);
         activitiesList.appendChild(activityCard);
 
         // Add option to select dropdown
diff --git a/src/static/styles.css b/src/static/styles.css
index a533b32..b336215 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -74,6 +74,47 @@ section h3 {
   margin-bottom: 8px;
 }
 
+.participants-section {
+  margin-top: 15px;
+  padding-top: 10px;
+  border-top: 1px solid #e0e0e0;
+}
+
+.participants-section h5 {
+  margin-bottom: 8px;
+  color: #1a237e;
+  font-size: 14px;
+  font-weight: bold;
+}
+
+.participants-list {
+  list-style: none;
+  padding: 0;
+  margin: 0;
+}
+
+.participants-list li {
+  padding: 3px 0;
+  padding-left: 15px;
+  position: relative;
+  font-size: 14px;
+  color: #555;
+}
+
+.participants-list li:before {
+  content: "•";
+  color: #1a237e;
+  font-weight: bold;
+  position: absolute;
+  left: 0;
+}
+
+.no-participants {
+  font-style: italic;
+  color: #888;
+  font-size: 14px;
+}
+
 .form-group {
   margin-bottom: 15px;
 }