Can't send text to some people

I'm experiencing a weird thing.  "Some" of the people I try to text to, I keep getting "Text not sent" messages.  I don't know how many people, just some that I've tried to send text messages to.  The two that I know for sure are my wife and my son, both on my Friends and Family list on Verizon.  This just doesn't make any sense.  I've made no major changes to my phone and rebooting doesn't seem to make a difference.

Added:  I have found a work around, but it's not really acceptable.  If I send to the phone number (not use a contact), it works.  But as soon as I try the contact method again, it fails to send.

Any ideas?  

I had the same situation. At first there was only one person I couldn't send texts to. That went on for a month or so and all of a sudden I couldn't send texts to another contact whom I'd been texting on a daily basis for months with no issue. Both were on different carriers. I called Verizon and spent an hour on the phone with them trying to fix it. They actually pretty much did nothing and I'm supposed to hear back from them in a day or so. However, I fixed it myself. 

I don't know if this will work for everyone - I'm using a Droid 2 on the Verizon network. Anyways, I realized they were my only contacts saved with their phone numbers in a +1 xxx-xxx-xxxx format. None of my other contacts had the + So, on a whim I decided to see if that was an issue, and texted the same exact numbers but without the + And...it worked. I took the + off both contacts and now I can text them just fine. Go figure...

The weirder part is I haven't modified either contact since I entered them months ago, so I'm not sure if this a sudden Verizon thing or if the +'s somehow got added on their own. So, hope that helps.

I had the same issues, first of all just restart your device, if ti doesn't help then restore your devices to factory setting and upgrade to latest version of android as many previous versions has many bugs that ruins user experience

I called Verizon and has spent many hours on the phone with them trying to solve the problem. They are in fact done virtually nothing, and I do not feel in a day or two. I, however, fixed.