Idea: Swim goggles to wear while exercising that use VR or augmented reality to make it look like you're being chased by a shark (or zombie or clown or whatever) to scare you to make you run or swim faster. Also: unlike a VR headset, you won't sweat in them and they won't break if you fall down; if you wore them in the ocean, you might misinterpret a real shark as a fake shark and get eaten, or they could augment your view of a dead coral reef to make it look prettier; Erik's "bacon-by-the-foot" patent
TBD