Monk Gyatso + Lightning Greaves + Nantuko Elder

Steps

1. Activate Lightning Greaves' equip ability by paying {0}, targeting Nantuko Elder.
2. Monk Gyatso triggers. Choose not to airbend Nantuko Elder.
3. Resolve Lightning Greaves' ability, attaching it to Nantuko Elder.
4. Activate Nantuko Elder by tapping it, adding {C}{G}
5. Activate Lightning Greaves' equip ability by paying {0}, attaching it to Monk Gyatso.
6. Activate Lightning Greaves' equip ability by paying {0}, targeting Nantuko Elder.
7. Monk Gyatso triggers, airbending Nantuko Elder.
8. The Lightning Greaves ability fizzles due to no longer having a legal target.
9. Cast Nantuko Elder from exile by paying {2}.
10. Repeat.