Blogger's note: what follows really is acknoweldged to not be all that smart, but sometimes fun and smart do not go hand-in-hand...sometimes fun is just that, fun, with no real thoughts of anything else. Oh, and I believe this could only happen in Ecuador!
What you need to do is invite just about every person you know, hope only half show, get a threat of rain that never comes to do just that, jam yourselves on top of a re-fitted bus that has its sides and seats torn away, which are replaced by six or seven rows of benches spanning the width that don't get used, flatten the roof, find a band to put on top of said roof that will play the same song over and over again, throw an addition on the back to fit 8 or 9, or 12 people but is really there so you can get to the band easier (if there's room up there), give everyone a whistle, a cup with a string to put around your neck so it doesn't get lost, have 48L of sugar cane booze on hand, throw the bus into drive, and cruise the city streets drinking, honking, drinking, whistling, drinking, dancing, drinking, ducking high-wires, drinking, ducking bridges, and drinking!!
Oh, and it certainly doesn't hurt to have the centre of these birthday shenanighans someone who can bring'em all so willingly together!
Twist. And have fun!