While we wait for Call of Duty Modern Warfare 2, Battlefield Bad Company 2, or the online shooter of your choice. Why not get a mini bite of online gaming with Battlefield 1943? At 15 bucks it has a good price point. Sure, it only has 3 maps with the 4th one unlocking once the community kills reaches 43 million (scroll down the page a little for the counter) The achievements overall are fairly easy to get. 100 online games played will take a good chunk of time since games last anywhere from 15-20 minutes. You are looking at around 33 hours to get the all achievements. A tasty appetizer while we wait for the the main course indeed.
UPDATE: Don't buy it yet, it is basically unplayable due to the lack of dedicated servers. Wait a couple of days.