Hello,
The PMBOK Guide 7th Edition defines project management as the application of knowledge, skills, tools, and techniques to project activities to meet the project requirements. By planning and managing the launching of a new website, it definitely sounds like you are applying certain skills, tools and techniques to do that in which case I would consider this as managing a project. If the same can be said for planning and managing the organization of a sporting event, then you are also managing a project. A project is defined as a temporary endeavour undertaken to create a unique product, service, or result (PMBOK Guide 7th Ed), and based on your description, the launching of the website and the sporting event would be considered a unique product and result. Even if a project is low in complexity, duration, number of resources, budget, etc it is still considered a project if you are creating a unique product, service or result. I hope this helps answer your question.
All the best.