This is an advanced and totally open sourced "advent calender" for FiveM which supports both ESX and QBCore. Preview Video
Simply download the script and unzip it into your resources folder or any sub folder of the resources folder.
Then ensure / start the script in your server.cfg and set up the config file to your own liking.
If you would like to contribute you can do it easily by forking this repository and then commiting the changes you would like to do through a Pull Request.
If you found an issue and want to report it, simply do it on the issues page of this github repository.