How can i talk loud/yell and not bug my parents?

Ok, Im 15. I live in an INCREDIBLY boring town, only enjoyment i get without having friends over is Xbox Live. And i always have fun yelling at people acting like im serious when im not, just for the hell of it lol, people think its funny. My parents dont care about my language too much (swearing) but they hate when they can hear me from downstairs and yell at me. i cant board up everything, but how can i make it where they cant hear me while still yelling, i have thin wood floors if it matters, thanks