Under Armour is an amazing brand and amazingly you can buy in today only a few dollars higher than IPO price. For the first few years of its existence investors saw its huge future potential and it was a great gainer. But it fell out of favor in 2008 and it seems to have been disregarded since then.
They are great in terms of product placement; see DirecTV's recent season of Friday Night Lights, where they are even worked into the storyline (coach Taylor uses his own money to buy the East Dillon Lions new UA uniforms after they burn their old, derelict uniforms) as well as smart in getting college athletic programs to contract with them for uniforms.
At some point the NFL's contract with Reebok as an exclusive uniform provider will be up, and I think there's a decent chance UA would win that contract. (Pure speculation.) Many NFL players already sport UA gear or are involved w/ UA in terms of promotion (Ray Lewis, most famously).
They talk a lot about 'authenticity'. This is in a way marketing schlock, but whatever it means, they have it. Buy while it's still off the radar.
Confidence is 8. My own money is in this one.