iPhone 3G running 2.2 (installed day it came out, so don't think it's the culprit) I'm not sure when, but no earlier than yesterday (probably today, but I can't guarantee I used a 3rd-party app today, although I've been in Phone, App Store, etc.), all of my 3rd-party apps stopped working. All built-ins work (Contacts, iPod, Maps, etc.), but no 3rd-party app does. "Stopped working" means you get the apps initialization screen, and then two or three seconds later it goes back to the home screen. ALL of my 3rd-party apps have this behavior (I've tried opening all 40 of them). For example, the Google Mobile app won't start, but the built-in Maps app will. I've shut it down and re-started it twice (held button at top right down until slider appears), to no avail. I haven't installed any new apps in the last two days. The only thing remotely unusual I can think of is that I was syncing some music this morning and had to stop it early (by sliding the "Slide to cancel" slider on-screen, not by just unplugging it from the cable). Any ideas on where to go from here?