Backstory: Festivals are all about expression. Firefly, burning man, Coachella, etc have all attracted large amounts of people that camp out multiple days. Festival goers dress up in crazy outfits and carry around outrageous signs to find their friends but they still sleep in the same boring, single colored tents.
The Idea: Multi colored and patterned tents.
Deep Dive: An e-commerce store that sells unique colors for tents including patterns and artistic designs. You could even allow users to upload their original artwork to be printed on tents. This could possibly branch into a woot shirt ( https://shirt.woot.com/ ) type of community where users upload their own artwork, the community votes and the winning designs are sold (the artist receives a small cut).
Validation: Patterns are appearing everywhere. Yoga pants quickly jumped from solid colors to crazy designs from stores like Lululemon and Athleta. Tents are another space filled with solid colors ripe to be changed.
Monetization: As a physical product, it's all about margins. You would have to run numbers on how much it would cost to print custom designs on the fabric and see if there's a market for it. You could probably attend a festival and presell a bunch of them before you invest any money.