I will add that I am mostly immune to caffeine - I can drink tea or coffee right before bed and still fall right asleep. It all stems from way back when I was in 8th grade, our English class presented a play. As the shy nerdy type I am, I had no desire to take one of the parts and be on stage, so I volunteered to work the lights (play with cool electronics? Why yes, thank you...). Of course no instruction was given, I had to figure out the board myself, but it was a pretty simple one, this was after all a public school and not a major theater house. During the intermission of the actual performance, they had coffee and such available. I never was much of a coffee drinker, but I discovered that with enough sugar it was quite tasty - I must have had 8 cups or more, I just kept going back for more the entire second half of the play. I don't think I slept that night. Ever since then, the effects of strong coffee or tea are so minimal as to not do anything about waking me up in the morning, and while tea often has more caffeine than coffee, drinking tea before bed does not keep my awake. I was working on an email migration for a client that had to be done overnight, and needed to be monitored - talk about boring, fire off some commands then stare at the scree for a few hours, repeat. To keep awake I decided to give one of those energy drinks a try - nope, did absolutely NOTHING for me.