Here are some tips when caffeine starts to either not work or, well, make you want to vomit rats:

  • Bright Light.  I've got a 300 watt halogen going in a 12 x 10 room and its having a noticable effect on my consciousness
  • Loud Music.  Hopefully my neighbors appreciate a Beastie Boys / Quiet Riot / Def Leopard / Dead Milkmen combination.
  • Cold.  I've got the window open and its chilly in here!  It works though.