I've been very interested in A.I. (artificial intelligence) for a long time but it just hasn't been advanced enough until recently. There have been a number of A.I. assistants that have gone on the market (siri for the iphone probably being the most widely recognized) but they've mainly just been advanced search engines that you can speak to.
I found this today:
A demo video for a new AI assistant that is being developed, and it was pretty funny. It isn't perfect but it does at least give the feel of having an actual conversation. There's a kickstarter up for it now than you can pledge for if you want to support them, check the link in the video description if you're interested.