Applying Hanselman's advice about conserving one's key strokes, & since I've been asked about TED, TEDx, TEDx Nile lately a couple of times, I'll sum up all the answers (to the questions I was asked) in one blog post to refer people to it whenever I'm asked again :D
So, first TED is a a foundation, that is mainly focused on sharing Technology, Entertainment, & Design ideas (that's where the name TED, comes from) through (mainly) a series of conferences held across Asia, Europe, US. There's also a TED prize for the best idea. TED later decided to share their talks with the world through their website. Also, the talks aren't bounded by technology, entertainment, & design ideas anymore..
Later, another project called TEDx was started. That's independently organized events (aka independent from TED foundation) where people share their ideas, or watch TED videos & discuss the ideas, in a TED-like environment/format.
Since TEDx project started, a lot of people -here in Egypt- were really anxious about bringing such an experience to us. The first one that came to my knowledge was TEDx Cairo, I was then introduced to TEDx Nile(which is the only & first TEDx in Egypt to come to reality, as far as I know), & TEDx Giza.Yet, I need to add that a fellow twitter pal claims that TEDx Giza was the first initiative :)
For more about the topic you might wanna read:
Wikipedia entry about TED
TEDx Introductory video
Review by fellow TEDster أحمد المهدى مسعود
My review about TEDx Nile (April 1st, 2010)
TEDx Nile hype on twitter
My favoorite Talks & speakers