For me, a mix of nostalga and music does the trick. For example tonight, was listening to Meat Loaf, and looking through a photo album of the first time I was ever introduced to W40K (this was maybe, 14-15 years ago?)
At that moment, I could recall everything about the photo, the smells, the sounds, the taste of the air (there has been a very heavy thunderstorm just before we arived), the layout.... and then bam... the euphoria kicked in... for the next 15-20 minutes... was just sat there, listening to music, eyes closed... without a care in the world.... no stress... no nothing... just... happiness and clarity.
The clarity is the part which I enjoy most... in those moments i'll decide my plans for the next few months... make business or personal choices.
So... lets get a thread going... if and when you ever have them... share it with us... what triggered it... what did you do or decide because of it?