A fellow in India (I’m assuming its the eponymous Arvind Gupta) has a whole site devoted to interesting things you can make with trash and junk. No banana peel particle accelerators, but a heck of a lot of neat and nifty gizmos that you can put together with balloons, paper, matchsticks and polonium.
I love these pecking birds.
There’s also a few science-y things in there in case you need to pull a MacGuyver and produce a railgun from some old film canisters, C batteries and a rare earth magnet.