I have tried many different activities. There is nothing I can think of that will be enjoyable.
Ok, I guess I'll have to bring out the big guns on this one. At the risk of sounding like a complete goner, I'll bring'em out. Has to be done 
https://www.youtube....EckGv-o#t=0m16s
This may sound like complete hogwash for more square, in-the-head kind of people. I however have been living it for a couple of years now, with absolutely glorious results. Endless adventure, fun, friends, girls, growth and so on. There is no way to be sitting on a chair, remain disconnected and keep thinking in-the-head about how this could work. You either put your movement and energy in, or you don't get the cookie.
There's nothing you should "think of" (in your head). That's absolutely not the place to go. You should be looking in your body. What puts fire to your balls to actually get up and do it? What did you always want to do, but maybe you've not done it, because other people thought it was not cool or whatever?
As long as you're alive, you have this available to you. Look inside, or look inside your present moment visual field, and ask, what's most awesome to do RIGHT NOW? THen do it, then see what next. Even a day of this will prove to you that you have PLENTY of pleasure and passion available.
The moment you lose it is when, instead of DOING the thing you want to do now, you start pondering and thinking about tomorrow, how does this connect, etc. YOu don't need to know how it connects. Do it and be engaged, or sit on the sideline asking why you feel disengaged.