I am going to start this list with a whole bunch of food challenges that are impossible that you can challenge your friend to do. Most of them I have tried with many friends and they are true so don't doubt me. They are very fun to do with some buddy's over and they are fun to tell someone if they do (food challenge) that you will give them 5 bucks or however much you want to go. If you can do it then you can flame.
***You can add on to it***
Drink one gallon of whole milk in an hour and keep it in your stomach for 20 minutes without throwing up.
6 saltine crackers in 1 minute.
24 marshmallow peeps in 5 minutes.
One full pound of steak in 15 minutes.
100 one ounce shots of beer in 100 minutes.
1 slice of any kind of bread in 45 seconds without drinking anything.
Eating a tablespoon of cinnamon. I'm not to sure on this one but my friend told me it.
