Sailing. Nothing else has had the capacity to be so pleasant some days, and to scare me witless others. Last year, I bought an ancient boat in eBay, and sailed it single-handed from Malden to London to bring it back on the Kennet and Avon canal. First it started taking on weather, then it got dark, then my gps stopped working, then the lights failed. Sailing has been arse-clenchingly scary, but brilliantly rewarding as well. (I made it, obviously. Had to turn around and head for Burnham on Crouch. If there's a bright centre to this universe, as Luke once said...)
And cycling. Golf. The usual old man stuff...