The left over weed definately still has actives in it.
about the amount you put in a joint got me and a mate more fucked than we ever did in our lives, i had quite a bit of tolerance as i had been smoking everyday for that past week. It was as if i had taken a dissociative and a psychadelic - my brain couldnt acknowledge my hands/legs were there. Everything became incredibly hilarious, and when we were forced to go to the supermarket we mustve looked VERY obvious as everyone kept staring at us. Color was simplified and vivid so i thought i was living in a cartoon world.
We ingested using a gravity bong (basically fill a 2L coke bottle with water, poke a small hole in the bottom cover it so water doesnt fall out, replace the lid with a cone/foil with holes in it, let go of the hole so water falls out and light the weed at the same time so the water creates suction pulling the smoke in. inhale)
The trick is to not overly heat your weed when vaporising it, so you are left with brown/dark green bud. when you inhale it should not be harsh at all. The vapour should taste like ass, its a weird sort of smell, a bit herby and a bit like popcorn :S, lol thats one of the things i hate about the vapo, the taste gets to you after continued use!
Heh, IMO you should just spend $1 and buy a lightbulb and test it out. Have a sesh with the vapo - see how you like the high. Save the vapo'd weed for the next day and have a sesh again with it - see if it works for you.