Get off the internet. That's probably what's keeping you up. Go read a book, lie in bed and listen to relaxing music, go for a walk or a jog and then come back and try to go to sleep again.
No, i don't need to sleep now. so i'm gonna see how this feeling goes. It's kind of a weird buzz. Not too euphoric
The best way for me to stay up indefinitely is to do something that doesn't require a lot of physical exertion but is highly mentally engaging. For instance, I could easily play chess for 40 hours straight and not feel a thing. and I blew through Final Fantasy VII back when I was 19 in a little over 2 days with just a couple hours of sleep. A couple times my cousin Tom and I have started a particularly involved board game (Axis & Allies, Shogun, or something along those lines) and not realize that a day or two has passed.
Yeah, Ive heard stories of poker players doing this, for insane amounts of time. in fact I can think of an interesting one. I'll try to dig it up. In fact that's what I did until i posted so much here. It didnt go so well. i didn't play marathon sessions tho
Amusing anecdote
One day David was stuck several hundred thousand in the Big Game and had been playing for 24 hours when I entered the game. Twice he made comebacks and got close to even and then informed me that he was quitting soon. Each time he lost a big pot and then that plan was shot. After another 24 hours I was up $500,000 and David was down over a million and playing recklessly. I was determined to stay until David quit, although his stamina had become legendary.
David went on a rush 60 hours into his session and, amazingly, got even. Most of his winning was at my expense, and I was now stuck $800,000. He looked at me with the innocence of a young child and said, "I think we have been playing too long and the other players have been alternating resting. We should quit." Apparently, he thought I wouldn't notice that the fact that he got even was the only reason he was saying this.