Borrow a keychain, a ring, and visually link the ring onto the keychain.
You know how long and how much work it takes to hook a key onto a keyring. But somehow, mysteriously, the magician merely touches a borrowed ring to a borrowed keyring and it is on it. This is Nexus.
The instructional video will teach you everything you need to know to perform this illusion. No trick props neccessary, this illusion is completely impromptu. Can be done anywhere, anytime, with a borrowed set of keys and a borrowed ring.