Spinning tunnels can be also called "Yak" Tubes since people do throw up in them.
A little boy was killed in one near Chicago a few years ago, he fell under some gears?
There has been a fair amount of good info on building them on-line if you can find it. I always thought of building one but standing it on-end and having people walk under the effect, this way the puke stayed in one place(as they are looking "UP"), it stayed on them! hahahaha!
I have my 45 foot high tower at the back of the house to put it in too!