Microsoft is holding a sale for XBLA, called ‘Extreme Shopping’. It will start today, March 29th and end on April 4th. There are a ton of games on sale, two of the SEGA games happen to be After Burner Climax and Crazy Taxi.
Each will cost you 400 MS points, half off what they originally cost. If you would like to see the rest of the games on sale, hit this link.