I’d like to take Kevin’s $0.02 in the coin-flipping word search.
First, I’ll buy a prediction contract that I will flip Heads. This will cost $0.50 for a $1 payout.
Second, I’ll buy the right to a futures contract: After the word is revealed and his search is complete, I will be given a prediction contract which pays $1 if Tails is revealed. If his expected posterior for Heads is 0.52 then the futures contract would have a value of $0.48.
In aggregate, I’ve paid $0.98 for a guaranteed $1.00 return.
Re: dehumidifiers
A standalone dehumidifier will heat the air more than sweating can cool it. You can see that from conservation of energy and thermodynamics: evaporating water (eg. when you sweat) absorbs heat , and condensing water (eg. in a dehumidifier) releases an equal amount. You also need to pay a bit of extra energy to run the machine and to overcome entropy.
Using an air conditioner to dehumidify doesn’t have that same problem, as it vents the heat outside.