This last weekend at a garage sale I picked up a box filled with supplies for use in dialysis by a company called Baxter. Most are a 12' extension set, the others are a so-called automated PD Set with cassette 4-prong. What does that mean? I have not a clue. However, the tubing is about the size of aquarium air hose and very flexible. So I thought it might come in handy for all sorts of projects from mini fountains/waterfalls, terrarium stuff, if you can envision it, and need lots of tubing for it and don't want to pony up...this is for you! Cut the ends off and go to work. The cassette thingie has at least one Y juncture and lots of pinch clamps.
Here they are out of the package.
The scary part is when I did a Google search to see what these things retail for. From the maker's website, the twelve footer is $165.99, and the cassette deal is, gulp, $845.92! I did check Ebay, and whilst you can sell this sort of thing, nobody is buying.
Anyway, if this sort of thing appeals to you shoot me an email and I will send you some.