Looking for some inspiration for your hackathon project?!
Peruse some of the following free APIs to integrate into your project!

Environmental APIs

Air Quality API https://docs.airnowapi.org
Weather API https://openweathermap.org/api
General Environment http://etwater.com/developer/
PDX Civic APIs http://www.civicapps.org
Forest Conservation APIs http://data.globalforestwatch.org/
EPA Web Services https://www.epa.gov/enviro/envirofacts-data-service-api

Television & Film APIs

Pokemon https://pokeapi.co/
Star Wars https://swapi.co/
Game of Thrones https://anapioficeandfire.com/

Design APIs

Unsplash https://unsplash.com/developers