Indy is the most basic and most utilized grab in wakeboarding today. That is not to say indy is played out, on the contrary, a well-executed Indy is a staple of wakeboarding that never loses its appeal. A legitimate indy can still be impressive and full of character, a creative interpretation of this grab is frequently a window to the amount of touch a rider has.
The mechanics of the indy are simple. Grab the board between your feet with your back hand. It is important that you grab in this area only. Your elbow can either go between your knees or behind both knees; the latter is a bit more stylish.
There is more to performing a reasonable indy than just the grab though. After a solid connection is made with the board, use your legs to characterize your presently squatting position. Normally this is done by extending the front leg and keeping the rear leg tucked up. "Poke it" or "bone it out," as it were. You can also add this grab to a number of other tricks: 180s, blind 180s, blind 3s, tantrums, fronts, back rolls, toeside back rolls to revert, half-cab fronts, scarecrows, back rolls to blind, 5s and 7s.