A lot of people find these activities aggravating, but I find both bowling and golfing very relaxing. So is spending an afternoon at the race track. Working out in the yard mellows me out as well, as well as sitting down, slipping on a pair of headphones and listening to some really great music...Beethoven's Ninth Symphony is very good to chill to.
Do stuff on my phone (social media, text, music, YouTube, this site) watch Netflix, play my playstation, hang out with the dogs, or have a nice hot bath. Sometimes I read.. (that's all for just relaxing though - not doing active stuff)