The IO Rodeo Colorimeter kit is building a basic easy-to-assemble (no soldering!) Open Source Hardware colorimeter - a basic scientific measurement tool, which uses different frequencies of light to measure properties of a liquid sample. The design looks very student-friendly, and is a good start on understanding that instruments aren't magic...
This 8-digit 7 segment display board is a nice module for old-school lots-of-digits output - if you were doing your own version of a DeLorean back-to-the-future dashboard, it'd be a good component to have :-) I'll note that in practice, a $60 refurb android tablet might be near-useless as a portable appliance, but it would make a great embedded display with graphs and whatever simulated-digit output you want... but I like LEDs so I backed it anyway.
Given how terrible Kickstarter is at actually helping me find interesting gadget projects (hey Amazon! buy them and force them to use your recommendation engine! :-) I owe credit for finding the LED display project to KickSaver - not actually a search engine, but certainly an interesting browsing alternative - you give them a price threshold, they give you kickstarter projects that need that amount to kick them over to successful funding. (Got a better idea? Fork Kicksaver on github and let me know what you came up with...)