Doing this required my to create a wide variety of elements from a QR code based scavenger hunt to a couple simple video games. Plus a website to hold all the games and QR assets.
You'll see the website here: shadowstatelarp.weebly.com
It looks pretty basic because most of the 20+ pages in this site are hidden from navigation so as not to spoil it for the players. Those pages were accessible only by locating QR codes hidden around the convention center.
My absolute favorite thing, however, was creating two text-based adventure games which players could run through to complete various objectives. "Help Desk" is a social engineering challenge, while "Dagger Quest" is more of a traditional text-based adventure game. Not only were they a ton of fun to make, they're proving to be a good marketing tool for us because now people can get a sample of our LARP anytime they want, not just at a convention.
It took a couple weeks of nights and weekends to pull it all together but I had a lot of fun doing it. The game ran at Archon and all the players seemed to love it, so time well spent in my book!