For the last 8 years I have rented gliders at Dillingham field on Oahu and given my friends and family rides. It takes about half a day to get checked out. Always has been a highlight of our trips.
Just remember to call and schedule the checkout and plane rentals well in advance.
The trade winds blow just about every day. You get off tow at 500 feet on the face of the ridge and you are up as long as your bladder can retain fluids.