Amazon once again has a Buy One, Get One Free Sale going on their game downloads. This one lasts thru the end of the month and you are allowed to choose the first game from anything in the Game Downloads Store other than the free downloads of Big Kahuna Reef or Cake Mania. You can try any (or all) of the games on a 30 minute game-time trial basis and if you buy one of them, you'll get a credit via email for the free game (not a coupon, just a credit). Once you have the credit email, you can buy any other game at the same or lesser price on the sale page, at no charge.
I've picked up a few of the games and they can provide a nice break. Since I usually play them on my netbook, I always use the free trial period, as I've found some of them won't work on it's smaller (shorter than standard) screen. Some of them really need an xternal mouse to work well, also. If only I could get the sprinkler system from Alice Greenfingers to work in Animal Crossing: City Folk (on the WII).