There's really not a formula for this.
Some Local Teams have a scratch space where people can add projects. Here's what ours from Michigan looks like: https://wiki.ubuntu.com/MichiganTeam/Projects
You can just add a section to your LocoTeam pages on the wiki, or you can just add a subpage to your namespace if you want to work on it before moving it on there. For example http://wiki.ubuntu.com/JorgeCastro/MyGreatIdea and then propose it to your local team list.
You're not too specific on what kind of activity you want to run, but you can check out these pages for examples on how to run events, it's a collection from all sorts of Local Teams on how they do things:
If you can't find information there, the Local Team leaders are on this mailing list if you want to ask questions about doing something specifically, chances are someone has already done it and made all the mistakes and learned from it. There are many experienced leaders on this list so if you want to run an event and are looking for someone to check it our for you that's where I'd go next.