This could be fun. Looking to get back at a coworker? Postal employee? Librarian? Priest? Sleeping brother or sister? The Sonic Grenade is your opportunity to turn any calm, serene environment into total calamity. Set the hard rubber grenade to one of three volume settings, pull the pin, and throw. 20 seconds later, sonic mayhem. Your target can't turn it off without the pin (which you'll be holding).
The best deal on the Sonic grenade is at ThinkGeek, where it's priced at just $12.99. If you're spending more than $30, use coupon code RAMEN for $5 off. Shipping and taxes vary by location.