Back in 1998, I created a "cheat sheet" containing the most common instruments and their ranges. The idea came after I found it too time-consuming to check the ranges in various books whenever I wanted to write music for a particular instrument. After all, it's difficult to keep everything in your head.
So I went through three or four books -- including Samuel Adler's "Study of Orchestration" -- and tried to collect safe ranges for each instrument.
This cheat sheet has proven to be useful for me. I have given it to my friends in the past who have used it in their composing work, so I'll put it here too for you to download and use as much as you want. I hope you find it useful in your music related activities.