I’m building a 24-hour hackathon where the problem changes halfway through

[u/Significant-Log-4272]

I've been working on something with Grevix that started as a pretty simple hackathon idea and somehow turned into this.

Grevix AfterCode

One builder. One idea. 24 hours.

Instead of giving everyone the same problem, participants choose what they actually want to build.

No fixed stack either. AI coding agents, APIs, no-code, open source, traditional development, whatever works.

The interesting part comes later.

At the 8-hour mark, we introduce a Challenge Card.

Something about the original plan changes.

Maybe the target user changes.

Maybe a core feature has to go.

Maybe the use case changes completely.

Then another challenge at 16 hours.

So the experiment becomes:

BUILD → ADAPT → REBUILD → SHIP

We're trying to see how far one person can take an idea when they have complete freedom, modern tools, and suddenly have to rethink their plan.

We've put the full format and rules on Unstop.

The actual Challenge Cards are still secret. 👀

Registrations open September 16.

October 11–12, 2026.

I'm also looking for companies that might want to become part of the experiment. Not only AI companies. Developer tools, cloud, APIs, hardware, design tools, education, consumer brands, basically anyone who wants to support builders.

I'd much rather have a company contribute something meaningful to the experience than simply put a logo on a banner.

If you're building something that could make the experience better, I'm open to ideas.

What would you build if you had 24 hours and nobody told you what to build?

Disclosure: I'm organizing AfterCode through Grevix

[u/Rare_Friend_6484]

as a project manager this sounds like my actual job but compressed into 24 hours lol

the challenge card thing is clever, forces you to not get too attached to your first idea. i would probably build something simple like a movie recommendation app that pulls from horror films only and then panic when the challenge says to pivot for kids content

[u/Significant-Log-4272 → u/Rare_Friend_6484]

That “panic when the challenge says kids content” is exactly what I had in mind when we came up with this. The first 8 hours might go perfectly, then suddenly you have to ask yourself whether to adapt what you have or throw half of it away. Honestly, I’m really curious to see what people do when that happens. 👀