Space shuttle Endeavour was to be in orbit by now, if all was going according to plan. But 2 heaters on the auxiliary power unit wasn't working, which caused the launch to be postponed. The external fuel tank(the orange one) was drained so technicians could get in and fix the problem. The heaters are really important because the space can get really cold at times and the APU doesn't want that.
NASA says the launch won't happen earlier than Monday, but I think it'll take a little more time than that.
In Japan where I live, the launch time was on 4 AM, so I had to get up early and tune into NASA tv on my iPod. (you can watch it from computers too- go to the link on the sidebar) I first went to my twitter app to say good morning to the excited(or so I thought) tweeters, and the first thing I noticed, the timeline was awfully quiet. And I found 2 people tweeting about "delays" and "heaters" and "too bad" and stuff. So I asked them "wwwhhhat!?" and they told me that the launch was scrubbed. So I went back to sleep.
I will definitely watch the launch next time!!