You get points for completing achievements
go here:
http://live.xbox.com...entSummary.aspxclick on a game and do the things on the list that you haven't completed yet
just about every game has 1000 points, all you have to do is complete all of the achievements, some are easier then others, but a good place to start is just going after the achievements for the games you already own.
Call of Duty 2: Play through the game again and beat it on Veteran Difficulty
Condemned: Play through the game again and collect 100% of the birds, metal pieces, mêlée weapons, fire arms, and evidence. Also do it without shooting any guns (you can do it on any difficulty)
GRAW: Finish the game on normal, play through the game on hard, play through the co-op missions, play on XBL A LOT (GRAW is a very hard game to get points from)
Oblivion: Play through all the different factions: Arena, Thieves Guild, Mages Guild, Fighters Guild, Dark Brotherhood, and complete the main quest-line.
Tomb Raider: Play through the game again on hard, Play through the game again in Time Trial Mode, Play through the game again and collect all of the bronze, silver and gold artifacts
Tony Hawk - Finish Story Mode and complete all the goals, Get all the goals in Classic mode, play every level on Xbox Live, get all the gaps
A lot of these games have strategies available in the sticky or the sub-forums
If you're looking for a new game to get you Cheap Points try: King Kong, Fight Night Round 3, Need for Speed Most Wanted, or any of the sports games. But honestly you've still got a lot of points to be earned with the game's you've got.