This is still 99 cents in the AppStore, so just a heads up. I have no idea what it is, but it's from Ubisoft so it probably is, well...something! Once again, I'm on my phone, so I can't post a direct link.
Think this went free once before as I remember my kids kind of liking it. It's a little takeoff of their Rabbids console games. This one really isn't a game. It's like having the Rabbid dudes inside your phone and you can do things to it (like poke it, etc.). Might be enjoyable for those with kids (especially those who dig the Rabbids games), but probably not for the rest of us. BTW: I think it was Rabbids Go Phone. Now, all I see on the store now is Rabbids Go Phone Again. So not sure if this is the freebie you're referring to.