Mine is... mowing the lawn! I know, I am kind of old-school with this respect. But I really enjoy this, being outside, getting my weekly dose of D-vitamins, etc. In addition, this is a quite useful activity for the house.

I was in fac about to consider biking a bit during the week-end, but the temperature is planned to reach 40 Celsius... France is hit by a heat wave at the moment, and I therefore probably won't bike...