It's from the Oasis in Mesquite. They're given to Grand Destinations Vacation Club members (timeshare owners) when they spend their timeshare week at the Oasis. Good for all sorts of discounts.

After we signed up for the regular slot cards I asked for a couple blank cards for my collection. I about fell over when the nice lady at the slot card desk gave me 1 of these and 1 of their regular cards (blank). I thought it was pressing my luck to ask for 2. Later when someone else was at the slot card desk I thought I'd try again and I asked for a blank card for my collection and only got the regular slot card. I just got lucky and asked the right person at the right time.
If you want I'll email you a scan of the back of the card which tells about all the discounts this card gets you.