In the Cubicle, the beginning stages of training, we teach our monkeys to respond to a laser pointer. This allows us to use the pointer to help give instructions to the monkeys. At first, the trainer will reward a monkey for simply touching the laser light. They then line up wooden blocks (starting with a single block to ensure the monkey's success) and point at the block they want the monkey to touch. They repeat this, adding more blocks, until the monkey can confidently choose the correct block out of seven identical ones.
Discrimination can be applied to any number of tasks in the home, so that a recipient can ask their monkey helper to choose a single light switch, power button, DVD, drink bottle, remote, etc. out of several items.