Many. But, I played the most physically demanding sport short of warfare... squash. I was hooked! And, I mean five to seven opponents in a row. Five hours on the court knocking them down EASILY one by one was fun. And these were not slouches. Some were provincial champs. Now, that was when I was in my early 20s. Anyone want to buy an Adidas racquet gym bag and three wooden squash racquets and some yellow dot balls (fuck the metal racquets)? BTW...anyone that plays blue dot is a fuckin pussie. Yes, I know that's all that the "elite" play... pussies all! I am keeping the fourth racquet... it works well on wasps and rogue robins that nest where they should not. I got a story about that robin... I gave her three chances but she wouldn't listen. Feathers flew.