There's plenty of weird science on display as the annual tech trade show known as CES kicks off in Las Vegas this week.

Some of the prototypes and finished products entrepreneurs are unveiling are so bizarre they have to be seen to be believed. Here are five strange devices at the top of our weird gadgets list.

1. E.Sensory's smart vibrator.

French start-up E.Sensory's Little Bird is a smart love toy that syncs up via bluetooth to a reading app. Users download the free app on their smartphone or tablet and can choose from various erotic short stories to be read in "vibrating version." Billed as the world's first smart vibrator driven by erotic e-books, the Little Bird also includes a vibrating message service and can be remotely operated by a partner. Price: $99.

 

2. Crazybaby's levitating hi-fi system.

The Mars device from Hong Kong-based startup Crazybaby is a wireless hi-fi system whose main speaker is a disk that floats in the air directly above the base subwoofer. The levitation is possible thanks to magnetic technology, and helps produce a higher sound quality, according to the company. How? Unlike traditional speakers, the Mars doesn't lose any sound through transference with physical objects. Price: $299.

3. Rythm's brain monitor.

The Dreem from Paris- and San Francisco-based neurotech startup Rythm is a wearable device designed to improve the quality of deep sleep. The headband product includes small sensors that monitor brain activity during sleep and "nudge" wearers into deep sleep with the intention of helping them wake up more refreshed. Rythm declined to disclose further details on how the product works, stating only that it is still in development, but says it anticipates launching the device during the first quarter of 2016. Price: Undisclosed.

CREDIT: CleverPet

4. CleverPet's canine game console.

San Diego-based CleverPet's Hub product is a game console designed to mentally stimulate dogs and teach them to solve simple puzzles. The pups earn treats when they push illuminated buttons with their paws. Co-designed by IDEO co-founder Mike Nuttall, the CleverPet Hub is the first of several products the company says will turn homes into "interactive virtual playgrounds" for pets. Price: Undisclosed.

5. BrainCo's mind control wearable.

The Focus 1 is a wearable device that Cambridge, Massachusetts-based startup BrainCo claims will enable individuals to use only their thoughts to switch on a light, control a robotic hand, and other perform other tasks. The product works by detecting brainwaves and converting them into various commands. BrainCo claims that using the product can hep improve an individual's focus level by stimulating areas of the brain that are less active. Price: Undisclosed.