get a ball (ex. soccer ball, basketball, volleyball). Not a baseball , tennis ball, etc. Keep it on your head for as long as you can. make sure you count out loud.
You record yourself with a camera. You take in a deep breath and puff up your cheeks as big as you can. You don't have to hold your breath. While your cheeks are puffed out see if you can talk, you last longer if you do it.
Hey! I'm back! And I brought a NEW measured comp with me! Balance the spoon on your nose and say the alphabet! See how long you can keep it there! Have fun!
OK, here's how it goes down. You try to rap off of the top of your head, and see how long you can go. If you stop and try to think up some more rhymes, that's cool, but you have a 5 sec.time limit. That's all! Don't cheat, but have fun, anyway!