Usually these days I'm with friends it seems and it's a festival of cigarettes, beer, movies, music, mixing, video games... when I'm alone, let's see
Sometimes I walk for a ways out into the canyons behind my house - then I usually get really baked and wander around until I come down a little. Sometimes things get pretty crazy. One time there was a pack of coyotes about 20 yards away, they all started howling and I bolted. Another time I was sitting down and discovered I was covered in ants. One time I almost stepped on a snake. Yeah, I don't go out to the canyon much anymore.
If I get really baked I often lie and trance out having an... well, an experience.
Sometimes I go for a swim or hop in the condo hot tub if it's empty. I don't really like interacting with strangers stoned. I might run, or drive to get food as I'm coming down.
Usually though it's some of food, adult swim, south park/chapelle show, computer, music, ripping cds for my new ipod, online poker, reading (read all of ender's game in one stoned 5 hour marathon a couple weekends ago) and of course jerking off. Like pretty much everyone else here

Like others who used to be dedicated to smoking, I've gotten bored of smoking very often... it works as one of many hobbies but not as a central focus of life.