The following are known Action Replay Codes for Xtreme Sports on Nintendo Game Boy / Color (GB / GBC). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark

Max Twitchy Shakes
0163f6c8

Max Medals
01c8fdc8
0101fec8

Max Points
0109f7c8
0109f8c8
0109f9c8
0109fac8
0109fbc8