AWS Start-Up Challenge (opens in new tab)

You fill out a form to register for the challenge and you get $25 free credit to build a start up on their platform.

The actual process for how it all works is here

http://aws.amazon.com/startupchallenge/rules/

Individuals or sole proprietors who have reached the older of 18 years old or the age of majority in their jurisdiction of residence and have the full legal capacity to participate in this Contest at time of entry.

Whichever is older, 18 or the age necessary to participate. Its odd wording, but it makes sense to say that you need to be reach whichever age is older, either 18 or the age of their jurisdiction of residence.