This is a list of games for fellow gamerscore whores that are easy to get a high amount of gamerscore in. Some may not be quick but they're still easy.
Anyway the list or retail and arcade games follow. It's not always easy to obtain the full amount but a high amount can be obtained easily in the following games:
Spoiler for Retail Games:
Spoiler for Arcade Games:
Any others you think should be added? Or wish to discuss?