[baxter001]

One I was at:

A constraint solving problem where you had a map with a grid and various clues gave you constraints like 'not within 2 squares of a bomb shelter'

A thermal imaging camera so you could detect which one of a set of 'sample containers' was warm and you should use the code printed on it elsewhere.

Combination locks where the combinations were given by giving the element names and you had to enter the atomic number (a table was on the wall)