EDH is probably my favorite format to play, alongside doing drafts and pre-releases. I currently have two decks and my wife has one.
This is my Yahenni deck: http://tappedout.net/mtg-decks/yeeaahhhenni/
I play more casually than competitive, just looking to have fun. The idea is to make opponents sac creatures and grow Yahenni and protect her. It definitely a fun deck, especially since my favorite color is black.
The other I have is Atraxa, which is a simple counters matter deck, no list for that but it's nothing different than you could find by googling really.
Then my wife's deck is a Tribal crazy cat lady deck. All creatures except the commander is a cat, the commander is Samut,Voice of Dissent. Just put out some creatures and attack really, with a mild equipment/token theme.