Can you give me a prompt to accomplish the following: A user wants to plan a surprise birthday party for their best friend, but they have limited resources, time, and creative inspiration. They would like ChatGPT to help them come up with a unique theme, decoration ideas, and fun activities that are feasible given their constraints. However, they also want to make sure that the surprise is not ruined by their friend accidentally finding out about the party beforehand. How can ChatGPT assist this user in executing a successful surprise birthday party without breaking the bank or tipping off the guest of honor?