I pass through Lincoln pretty regularly to visit my old man on the Farm (Hebron, NE area).
DasStig -
https://www.facebook.com/NQS-Performance-340169165053/
Just keep your eye on that page, they typically run 4 per year. They are held on the, what was, 0.6mi go-kart track (paved road course, plenty wide for a single car) in Marshalltown. It's a mix of domestic, Japanese and European (occasional exotic) vehicles that show up. No ego's or anything like that and it's a good time. The classing isn't as uptight as the SCCA event around here either. My outgoing 2008 Cobalt SS/Turbo was stock class and running at the top of that class. A lot of the folks involved with NQS can instruct/ride along too if you are not comfortable doing it solo yet.
$25 to race, and lasts from sun-up to sun-down basically. They have approved helmets you can use, but I bring my own for my kid and I.
I mention ego's because, and maybe its just me, but the couple times I've done to SCCA sanctioned events around here... my experience was not good.