I listen to music, most often. It depends on the mood. I find non-vocal (instrumental) pieces best. Music from the "Halo" videogame franchise is pretty solid and varied enough for me.

I go to InterPals and other social networks! Conversations with your friends always keep you away from bad thoughts...
Another way is to buy lots of fast food, get some awesome movie and enjoy the whole evening!
During all that I turn off my cell phone, close the door of my room, so no one would bother me and so there's just me and me...
that's when I'm stressed...

as for loneliness, there's no cure
something this feeling eats you from inside and nothing helps and no one
you have to just live through this pain

sometimes....

All the time and its the worst feeling in the world.

I have!

When i feel that way, i watch south park.

When I feel that way, I usually lurk on sites like this, hoping someone will notice me and talk to me, but I am usually disappointed.

Whenever I feel lonely I just turn on the engine of my car and enjoy the traffic jam with the radio on. Works everytime.

I feel lonely often, and the ways I deal with it are to either write songs/poetry, make art, or try to go for a walk or something in the woods. That usually helps me feel better.

Talk to the mirror