An incentive for drinking beer (Angkor or Cambodia), as if you need an incentive, is that with every beer you have the opportunity to win something. When opening a beer, you pull the metal tab and look on the bottom to see if it's a winner. This is something that is ongoing, not seasonal or a special promotion. You can drink beer and win all year round.
The most common is another beer (about 1 out of every 5 on average), money, a motorcycle, or even a trip to somewhere. If it's a free beer, some shops require that you bring the can back with your tab to claim your prize. Otherwise, you pay the 10 cents for a new can. For the larger prizes it's required to have the can with the tab.
The photo on the left is me winning a free beer today, as shown by the picture on the tab I pulled to open it. The photo on the right has stacks of winning tabs being tied together in groups of 24 by the shop owner. When ordering more beer for the shop (going across the street to the one place that gets all of the cases), they can 'cash' these in for new beers.
The most I've ever won was $1, but it was an exciting day. When you're sitting around with friends having some drinks, each winner is a cause of a celebratory cheers and congratulating the lucky winner.