Let's say you've read on Androidheadlines.com about a new update or bug fix for your device. Naturally, you're excited and want to download it as soon as possible. You enter into the phone settings and manually check for the update, but the phone tells you that nothing is available right now. If you're like me, it's wash, rinse, repeat until the update finally shows up.
However, there can be a lag between when an update is made available and when your phone normally checks to see if updates are available.
This tip from Lifehacker shows how you can force your phone to check for system updates.
Open your dialer and input *#*#checkin#*#* (substitute the numbers on the dial pad for the letters). This should force your phone to check for any updates that you might not be aware of.
Note that the trick doesn't always work. I tried it on my Droid 2 with no luck, but it's worth giving it a shot.
Let us know if you had any luck and what device you used.