iPhone won't charge

Here is the first of two wierdnesses I have experienced today. This first one involves my iPhone appearing to not recharge. I plugged it in to a wall jack last night. when I unplugged it, it showed that it was half full. I thought that was a bit odd, so when I got to work I plugged it in again. An hour or so later, it was still half full. So I thought maybe the wall plug thing isn't a good idea so I plugged it into my Mac. A little bit later, still half full. By this point I am getting worried. Oh noes! I have a faulty iPhone. Nah. I just restarted it and it showed that it was full.