Hint: Birthday
The answer to this puzzle is:
1. BALLOON
2. CAKE
3. TREAT
4. FOOD
5. PARTY
6. CELEBRATE
7. PLATE
8. JUICE
9. CUPCAKE
10. GAMES
11. GUEST
2. CAKE
3. TREAT
4. FOOD
5. PARTY
6. CELEBRATE
7. PLATE
8. JUICE
9. CUPCAKE
10. GAMES
11. GUEST