Air Sahara offers a "if we delay, we pay" policy on all non-stop flights between DEL, BOM, BLR and CCU. Simply put, it will pay Rs 1500 cash or Rs 3000 ticket credit (for S2) if there are any controllable delays, such as maintainence problems or crew problems, etc. It will not, however, offer compensation if the delay is caused by something beyond its control. Fair enough. In reality, it won't be paying out that much, but it is nevertheless a nice touch - especially if getting the cash or credit is simple and quick.
The full details are here:
Which other airlines offer such a policy and are they, in your opinion, a hassle or a blessing?