Everyone's heard about filling the victim's room with balloons,

Everyone's heard about filling the victim's room with balloons, right?
(balloons are great, especially if the victim is your SO and you come by
later, acting innocently, and suggest...well, you get the idea.)

Unfortunately, inflated balloons are bulky to carry, and it can take a
dangerously long time to inflate them in the victims room. There is a
solution. (I've actually done this, it really *does* work, even if it
sounds ridiculous) Go out and get 2 or 3 styrofoam beer coolers. Inflate
the balloons in the privacy of your own room. Fill the beer coolers
with liquid nitrogen. (at 77 K it can liquify air) Stuff all 2 thousand
or so inflated balloons into the beer coolers. (don't worry, they will fit,
liquified air occupies *very* little space) You may need a refill or 3 of
liquid nitrogen. Get a friend or 3 to help carry the coolers to the victims
room. Make sure there isn't any paper or other water-damagable stuff on
the floor. Strain out the majority of the LN2 and dump the inflated balloons
onto the floor. Close the door. (if there is a window or transom, it's
great fun to watch the balloons reinflate to fill the room)