Soldier Ant 

Awright, here it is. This run-only Applescript asks for an XBox Live gamertag, and returns an hours-and-minutes count of the last time that gamer was online. (Or at least, online in Halo 2.)

Some caveats:

1. This works perfectly, except when it doesn't. (That is, I've made no attempt at error-catching or input validation - so if you enter spaces or weird characters? Who knows what you'll get. If the app times out on your query, and then quits? It's because it threw a 'Type 1 error' which the script ignores. Some of the weirdness is coming from Bungie's side, I think.)
2. This is fairly slow. I'd say it averages 6 to 10 seconds to run. But it should still beat firing up a browser and navigating through bungie.net. (It's also easier to run from work and not look like the loser you know you are.)
3. Oh, and I think my math is off on the hours/minutes conversion. I'll work on that for the next version.
4. Until I can fix some of the above annoyances, I am only distributing this as a compiled executable - no source. (I'm also kinda embarrassed about some of the lame things I had to do to get this to work, so.. my kimono will remain closed on this one.) Once it's respectable, I'll slap the source up for the taking.
5. This should go without saying, but.. this is an Applescript. Therefore it will only run on Mac OS. (Actually, it requires at least OS X, and in fact hasn't been tested on anything other than 10.3.8) YMMV (tee-hee! I always wanted to say that.)

1. Extract Halo2Status.app from the ZIP file.
2. Doubleclick it to run it.
3. Follow the prompt, then wait (for 6-10 seconds. Weren't you paying attention?)
4. Leave a comment here if this thing works for you. Or if it doesn't. In fact, just leave a comment.