Easy Arcade Achievements?

I'm in a gamerscore race with a friend and have a bunch of ms points. Suggestions?

your sad?

Adventure games:
You can get 200 pts out of any Wallace and Gromit Episode easy.
Monkey Island Special Edition (You should own this regardless of racing.)  
I've heard that early Xbox Arcade games like Cloning Clyde and Marble Blast are good places to get achievements.
 
Outside of Xbox Live Arcade, games like King Kong and of course... Avatar....Will most certainly boost your score with an easy 1,000 for each. Early Xbox games like Condemned are good achievement buckets :P

Boom boom rocket is pretty fun and got pretty easy achievements. 200 points in no time :D

Galaga is easy and fun too.

I got the full 200G in Banjo-Kazooie, Banjo-Tooie and Portal Still Alive, but it took me a while for them even if it wasn't too hard.
 
You should be able to get 150G+ in UNO fairly fast with Xbox Live. Secret of Monkey Island is another good one that I'm going through now, will try for the full 200G once I've finished my first proper run through. The Maw is also fairly easy to get a lot of points in and the full 200 (or 250 with DLC) if you're willing to put in a little bit of extra effort.
 
I'd disagree on Marble Blast Ultra; I think getting under par and all the easter eggs on the later levels can be quite tricky, I only ended up with 50G or something after going through it.

terminator salvation will get you the full 1000 in four hours

Don't. Just don't. 
 
Don't support crappy developers with buying games just for achievements. If you want a good game with easy achievements, just get early sports games from 05/06. I got 1000 GS easily from NBA 2k6, and now, it'll only be about 5 bucks from an store.