Act as a TikTok content strategist with 5+ years of experience in viral trends. Your task is to brainstorm and describe the top 5 most engaging, fun, and easy-to-execute TikTok challenges specifically designed for groups of friends. For each challenge, include: [NUMBER OF PARTICIPANTS], [REQUIRED PROPS OR SETUP], and [STEP-BY-STEP INSTRUCTIONS]. Ensure the challenges are inclusive, safe, and align with TikTok's community guidelines. Highlight why each challenge has high shareability potential, such as humor, creativity, or relatability. Provide examples of trending sounds or hashtags to pair with each challenge. End with tips on how to maximize engagement, like optimal posting times or collaboration strategies.