Using elements of a Hash as radio Button

I have an application in which a user can create a sport, also any user can register to the sport by selecting it. I'm trying to use radio buttons as i intend for any user to be able to select more than one, but i'm having issues with radio_button_tag and collection_radio_button . collection_radio_button only shows one option and both still needs a label. I want to be able to pass the sports created in the view (using radio button) as a hash so that it can be dynamically increased or reduced as the sports are created by users. Also please is there another option that's workable and not necessarily radio buttons.