you think a lay person would know what a wii and ipad are? Most "lay person" type people who I talk to refer to all apple family products as iPhone even one who calls hers the iPhone laptop....
Best way to describe it is a portable games console that can also connect to your TV for home console play, like a cross between a Game boy and a Playstation (far more likely to be understood by more "lay" people I think)
Why not check me out on youtube and help me on the way to 2k subs over at www.youtube.com/stormcloudlive