I don't live in Lincoln, or even in Nebraska, but whenever I'm in Lincoln for work, I attend yoga or pilates classes at Haymarket Pilates & Yoga Center. The instructors are excellent and the atmosphere is relaxed and friendly. It's located in the Haymarket area in downtown Lincoln. Be sure to call ahead to reserve a space in the class - it's a small studio. The cool thing is, they provide the yoga mats! Very nice when you're on the road for work.