Up for grabs in the challenge is a 42" Hitatchi UltraVision Plasma TV for the two overall winners, and a HD-DVD player, wireless steering wheel and wireless headset bundle for the four runners-up. What's more, 100 further top-scorers will also win 500 Microsoft points each - ideal for a pre-christmas desktop theme and/or festive gamerpics.
The first of the two challenges, the Lumines Live! challenge is set to run between December 17 and December 23, with the top 105 people in the Time Attack 60-second mode leaderboard at the end snatching prizes.
Small Arms meanwhile will also award the top 105 players, based on ranked match activity between 24th and 30th of December. Winners will be drawn at a minute past 12 on the 31st, giving you an opportunity to get drunk and countdown to midnight at least two days in a row.
To stand up to the Challenge you'll need to pre-register over at Xboxlivetournament.com